0. Before Class Begins

  1. Buy your books
  2. Buy and register your iClicker https://www.iclicker.com; bring it to class the first day and every day
  3. Do Assignment 1

Complete all of these by 5:00 pm Mon Jan 20


Assignment 1:

  1. Read the syllabus at:
  2. Using the information in the syllabus, think up a question that should be on the FAQ—the Frequently Asked Question—list for the course
  3. Answer the question you thought up
  4. Upload your question and answer to your account at the course on canvas at: https://bcourses.berkeley.edu/courses/1487685



1. Preliminaries

1.1 What Is the "History of Economic Growth"?

"Growth" is a word borrowed from the Norse groði in the late 800s and 900s when Anglo-Saxon and Norse merged in the creole that became the Mercian dialect of Late Old English. Its root meaning is: the process of vegetation becoming green and becoming larger.

"Economics" is two Greek words mashed together: "οικοσ", "oikos", and "νομοσ", "nomos". "οικοσ" refers to a household considered as an array and flow of resources. "nomos" are the laws, the rules, the patterns, or the nature of something. "οικοσ-νομοσ" are thus the rules or patterns of managing resources.

"History" is another Greek word, Herodotos of Hallicarnassos's "ἱστορία". It means a set of inquiries into something or things, inevitably including their developent over time.

Thus you might paraphrase the course title as: "a set of inquiries into how resources and the patterns of their management blossom and flourish over time". And we will stress the "over time": we start 200,000 years ago, and will—I hope—end up talking about May 2020.

Topics covered include:

  • human sociability;
  • the discovery of agriculture and the domestication of animals in the Neolithic Revolution
  • economic growth in ancient, Malthusian societies
  • the origins and maintenance of gross inequality
  • the Commercial and Industrial Revolutions
  • modern economic growth
  • theories and evidence about the institutional, geographic, and cultural determinants of growth: international prosperity differentials and the so-calledl "middle income trap"
  • OECD convergence and East Asian miracles
  • the political economy of growth and stagnation
  • the stubborn persistence of poverty



Bill Bryson (1991): The Mother Tongue: English and How It Got That Way https://books.google.com/isbn=0380715430
Herodotos: The Histories https://web.archive.org/web/20150318135740/http://www.isidore-of-seville.com/herodotus/
Dotan Leshem (2016): Retrospectives: What Did the Ancient Greeks Mean by "Oikonomia"? https://www.aeaweb.org/articles?id=10.1257/jep.30.1.225
Wikipedia: Heptarchy https://en.wikipedia.org/wiki/Heptarchy


1.2 Administration: The Syllabus

Economic Growth in Historical-Comparative Perspective

J. Bradford DeLong, TBA, TBA

Spring 2020 | Economics 135 | Birge Hall 50
Lectures: Tue-Thu 9:00 am; Tu Jan 21-Th Apr 30
104 Wed 8:00 am Etcheverry 3119
102 Wed 10:00 am Valley Life Sciences 2070
106 Thu 2:00 pm Dwinelle 179
105 Thu 5:00 pm LeConte 385
103 Mon 8:00 am Etcheverry 3119
101 Mon 10:00 am Valley Life Sciences 2070
Draft 1.0


Course website: https://bcourses.berkeley.edu/courses/1487685
Course notes: https://www.icloud.com/keynote/0XSXpI19V8lQ7wy_MRh54Qg8A
Course description: This course examines the idea and reality of economic growth in historical perspective, beginning with the divergence between human ancestors and other primates and continuing through with forecasts for the 21st century and beyond. Topics covered include human speciation, language, and sociability; the discovery of agriculture and the domestication of animals; the origins and maintenance of gross inequality; Malthusian economies; the Commercial and Industrial Revolutions; modern economic growth; international prosperity differentials; OECD convergence and East Asian miracles; the political economy of growth and stagnation; and the stubborn persistence of poverty.
Course requirements: TBA
Course deadlines: TBA
Course readings: Lecture notes, plus four very short books: Robert C. Allen (2011): Global Economic History: A Very Short Introduction https://books.google.com/?isbn=0199596654 (HC51 .A56 2011); Robert C. Allen (2017): The Industrial Revolution: A Very Short Introduction https://books.google.com/?isbn=9780198706786 (HC254.5 .A664 2017); Christopher J. Berry (2019): Adam Smith: A Very Short Introduction https://books.google.com/?isbn=0198784457 (B1545.Z7 B47 2018); Partha Dasgupta (2007): Economics: A Very Short Introduction https://books.google.com/?isbn=9780192853455 (HB171 .D26 2007)
Lecture response system: an iClicker https://www.iclicker.com
Course prerequisites Econ 135 requires:

  • Econ 100 or the equivalent, or more
  • Math 1 or the equivalent, or more
  • I—Brad DeLong, the professor—am of the opinion that by now you should have taken Data Science 8 or the equivalent, or more, as well, simply by virtue of your being students at U.C. Berkeley here one-fifth of the way through the 2000s


Contacting You, Contacting Us: The staff use email to contact you. You are responsible for reading your email. Emails sent to the class are archived at the bCourses “pages” tab: http://bcourses.berkeley.edu. Email sent to the staff must have “Econ 1:” plus a descriptor as the subject. For instance: “Econ 1: Announcement Requested” or “Econ 1: Question about Enrollment”. Emails should be signed with both first and last names.

Piazza: We use Piazza in lieu of emails for Q&A. Post your questions on Piazza. Everyone – the instructors and students – then has the opportunity to answer your question. Answers can be edited, wiki fashion. The instructors can give a ‘thumbs up’ to good student answers. Others with the same question can see the conversation and chime in. At the end of the term, students whose questions or answers received the largest number of “good” votes from classmates and instructors will receive a few extra credit points. If you didn’t receive a Piazza welcome email, sign up at http://piazza.com/berkeley/spring2020/????.

Staying in the course: To stay in the course: You must attend the section you are assigned to in the first two weeks.

Adding the course: We expect students who are added to the course after the first day to have completed all work for the course, on time. If you are on the waitlist, do all the work: exercises, activities, assessments, and submit your assignments to the GSI of your waitlisted section. Nothing is accepted late just because you’re on the waitlist. For info on adding the course, go to https://www.econ.berkeley.edu/content/course-enrollment

Tutoring: Economics Department grad students offer free tutoring. https://www.econ.berkeley.edu/undergrad/home/tutoring. Twitter @CalEconTutoring. A list of tutors-for-hire (about $50/hour) is also available at the Econ Dept Tutoring Center website. Also the Student Learning Center (SLC) offers Study Group and Drop-in Tutoring for Economics 1. These services are free for registered Cal students. Additional information is available at http://slc.berkeley.edu/econ.

Meetings: To help the instructors get a better sense of how the class is going, every week (after the first week of classes), six students will be selected at random, and will meet with me for 30 minutes, to explain their work and to answer questions about it. You may be selected on multiple weeks, if that's how the random numbers come up. This is not a punishment, but a way to see whether the problem sets are really serving their goal of helping you learn the course material; being selected will not hurt your grade in any way (and might even help).

No Announcements in Lecture: No announcements are made in lecture. All announcements are sent via email and then posted on bCourses “pages” tab. If you would like to make a written announcement, send it to the staff for inclusion.

Disability Accomodation

DSP: If you require disability-related accommodations for exams or lecture, if you have emergency medical information that you wish to share, or if you need special arrangements in case the building must be evacuated, please email or speak with us by January 19. Do so even if your Disabled Students' Program http://dsp.berkeley.edu appointment is after September January 19. At least 2 weeks before the exam, you must also obtain a Letter of Accommodation (LOA) from the DSP. The DSP's own internal deadlines require that requests for exam accommodation must be received and acknowledged by the staff at least two weeks before the exam.

Coursework and Requirements

iClickers: In each lecture there will be questions to answer with your iClicker. If you answer more than 3/4 of that day’s questions, you earn 1⁄/2 point. It doesn’t matter whether your answer is “correct.” iClicker points are used to make up for missed points on problem sets. Anyone observed using two iClickers will have both iClickers taken away and held by the staff, and all points for both iClickers will be zeroed out for the term.

Problem Sets: There will be __ problem sets, each of which is worth 10 points, distributed in lecture and posted on the course website that you are to complete and submit to your GSI. Problem set answers must be submitted on the provided answer sheet; problem set essays are submitted via bCourses. Problem sets are due at the beginning of section. Problem sets lose 5 points if they are submitted after the start of section. No problem sets accepted more than 24 hours after section begins. Problem Set #1 Due second section, week of September 9 Problem Set #2 Due second section, week of September 23 Problem Set #3 Due second section, week of October 21 Problem Set #4 Due first section, week of November 25 You may study with other students, but your problem set answers must be in your own words. You may not prepare “group answers” nor post your answer to Piazza. Essays must be your own work. If you copy someone else’s answer or essay, or if you prepare or post group answers, that is cheating. If your problem set is the same as someone else’s problem set, in whole or in part, you both receive a zero (0) regardless of who did the work and who copied. Problem set solutions will be posted on the course website. Read the solutions carefully; they are far more extensive than your own work.

Sections are not supposed to be mini-lectures; it is a hub of active learning. Why active learning? Because every bit of research shows that we learn best when we engage in active, not passive, learning. Sections are where you work with the concepts. Think of section as a lab, akin to a chem or physics lab. You will work in small groups, with work to be completed in lab each day.

1/10 of your course grade will depend upon your participation in section. You are required to do four things...

Exams are held only at the times noted. If you experience an emergency that is clearly unforeseeable and unavoidable that prevents your attendance at a midterm exam, you must contact us in the teaching staff before the midterm begins. Explain the situation and provide documentation. We will consider your case.

Student-athletes and musicians are expected to be familiar with the policy on academic conflicts: https://academic-senate.berkeley.edu/sites/default/files/guide-acad-sched-conflicts-final-2014.pdf.

There is no make-up final. If you miss the final with an acceptable excuse covering an unforeseeable and unavoidable event, you will take the—different—final for the next—different—instantiation of the course in the fall semester. The comprehensive final examination will be held on ___, in a room that will be announced by email and on Piazza. The final will cover all material presented in lecture, section, and the assigned readings.

If you can’t take the final as scheduled, don’t take this course.

Academic Honesty: In fairness to students who put in an honest effort, cheaters will be harshly treated. Any evidence of cheating will result in a score of zero (0) on that assignment. Cheating on a midterm, the comprehensive essay, or the final exam results in an “F” for the course. Cheating includes but is not limited to: bringing unauthorized written or electronic materials into an exam, using unauthorized written or electronic materials during an exam, copying off another person's exam or assignment, allowing someone to copy off of your exam or assignment, having someone take an exam or assignment for you, changing an exam answer after an exam is graded, and plagiarizing written or other materials. Incidences of cheating are reported to Center for Student Conduct, which administers additional punishment. See also http://sa.berkeley.edu/conduct/students/standards.

Everything you turn in for a grade must be your own work, or a clearly acknowledged borrowing from an approved source; this includes all mathematical derivations, computer code and output, figures, and text. Any use of permitted sources must be clearly acknowledged in your work, with citations letting the reader verify your source. You are free to consult the textbook and recommended class texts, lecture slides and demos, any resources provided through the class website, solutions provided to this semester's previous assignments in this course, books and papers in the library, or online resources, though again, all use of these sources must be acknowledged in your work.

In general, you are free to discuss homework with other students in the class, though not to share work; such conversations must be acknowledged in your assignments.

You are, naturally, free to complain, in general terms, about any aspect of the course, to whomever you like.

Should you be unsure about what is or is not appropriate, please ask us before submitting anything: there will be no penalty for asking. If you do violate these policies but then think better of it, it is your responsibility to tell us as soon as possible to discuss how your mis-deeds might be rectified. Otherwise, violations of any sort will lead to severe, formal disciplinary action, under the terms of the university's policy on academic integrity.

Initial Assignments

Syllabus FAQ Assignment:

Introduction Letter to GSI: For your second section meeting, please write a 1-page letter of introduction of yourself to your GSI. Submit a hard copy at section. Include your name, its pronunciation, your pronouns, and anything about yourself that you would like to share. Please embed a photo of yourself; doing so will help your GSI learn your name. The paper will not be graded nor returned. (Include the name we will see on the roster and, if different, your preferred name. Remember you can set your preferred name in CalCentral too: http://registrar.berkeley.edu/academic-records/your-name-records-rosters)

[1] In the first section, there will be a math pre-assessment (quiz). If you score less than or equal to 3 of the 4 possible points, you can increase your score to the full 4 points possible by subsequently working on your math skills with one of the department’s (free) graduate student tutors. (4 points possible) [2] In each lecture, an exercise ("the Blue & Gold Exercises") is distributed. You are to complete the B&G exercise and take it to the section following lecture where your GSI will check to be sure it has been completed. No late B&G exercises accepted. (Max of 20 points will be counted although 26 are possible; points based on attempt not on accuracy.) [3] Each section, you will discuss that day’s reader article(s) and do small-group work on problems (“the section exercises”). You may occasionally have in-section quizzes. Your GSI will provide more information in section. Absences result in 0 points for that day. (1 point per day; max of 20 points will be counted although 24 are possible.) [4] After MT1 and MT2, you’ll complete a “post-exam reflection” – a series of questions inviting you to reflect on how you prepared for the exam and whether you want to make adjustments to your preparation. You’ll submit the reflection on bCourses within 7 days of the exam. No late submission allowed. (3 points per reflection; points based on completion.)


How and Why to Study

This is Berkeley, the finest public university in the world. Here we expect you to acquire deep knowledge of the subjects you study, so that that knowledge becomes part of your intellectual panoply: a toolkit that you can and will apply in new and different situations. Highlighting, re-reading, re-listening may have worked for you in the past. But they are not very likely to be sufficient now.

We recommend: (1) read, making notes as you read, writing questions in the margins, and noting other historical and modern parallels; (2) listen to the lecture, taking notes; (3) do exercises—in lecture and in section—to reinforce the "what if?" lessons of the historical arguments made; (4) discuss, with your friends or your study group or in your section; (5) read again, this time asking yourself "how would I explain this to some idiot?"; (6) take your notes and write them up in a more connected and intelligible form, again with an eye toward—"how would I explain this to some idiot?"—and realize that the idiot is you, as you will be when you are reviewing before the exam; (7) let things sit for two weeks and then read the written-up notes, and then go back to the readings or to the lecture videos where things are unclear and confusing.

As a final word of advice, "what is the least amount of work I need to do in order to get the grade I want?" is a much worse way to approach higher education than "how can I learn the most from this class and from my teachers?".

In addition, we recommend Stephen Chew as a source of useful insights and practices.



Stephen Chew: How to Study https://www.samford.edu/departments/academic-success-center/how-to-study


Limits to Confidentiality: As UC employees, all course instructors and tutors are “Responsible Employees” and are required to report incidents of sexual violence, sexual harassment, or other conduct prohibited by university policy to the Title IX officer. We cannot keep reports confidential from the Title IX officer, but the Title IX officer will consider requests for confidentiality. There are confidential resources available to you, including the PATH to Care Center http://sa.berkeley.edu/dean/confidential-care-advocate.



Lecture Notes https://nbviewer.jupyter.org/github/braddelong/long-form-drafts/blob/master/econ-135-lecture-notes-history-of-economic-growth.ipynb Robert C. Allen (2011): Global Economic History: A Very Short Introduction https://books.google.com/?isbn=0199596654 (HC51 .A56 2011) Robert C. Allen (2017): The Industrial Revolution: A Very Short Introduction https://books.google.com/?isbn=9780198706786 (HC254.5 .A664 2017) Christopher J. Berry (2019): Adam Smith: A Very Short Introduction https://books.google.com/?isbn=0198784457 (B1545.Z7 B47 2018) Partha Dasgupta (2007): Economics: A Very Short Introduction https://books.google.com/?isbn=9780192853455 (HB171 .D26 2007)
iClicker https://www.iclicker.com


2. The Big Picture

Fully half of what this course has to teach is contained in one table and one figure. The table provides the eagle's-eye—the 747's-eye—view of human population and production over the past 70000 years:


Source: https://www.icloud.com/numbers/0jaPx8AjooD2TDbNM4Og3Z2ow

The figure shows how the relative wealth of human populations as they are gathered in nations has spread out over the past two centuries:


Source: https://www.gapminder.org/tools/

Now let's briefly unpack what this table and this figure tell us:


2.1. The Gatherer-Hunter Age: 70000 to 10000 Years Ago

2.1.1. Numbers

70000 years ago—when the descendants of those who had been anatomically modern humans became behaviorally modern humans—there were fewer than 100,000 of us on the globe, perhaps many fewer than 100,000, perhaps shortly before (meaning a few thousands of years before) there had been only 1000 breeding pairs that have given nearly all of us nearly all of our genes. As a result, there is today more genetic diversity in a typical fifty-animal baboon troop than in the entire human race: we are all more closely one another's cousins than is the average baboon with his or her troopmates. Becoming behaviorally modern, however, gave us a large edge. Over the subsequent 20000 years we spread out within our common motherland of Africa. And starting perhaps 50000 years ago we launched ourselves across the Red Sea from the Horn of Africa to Yemen, and began to spread out over the entire world. By 10000 years ago we could be found nearly everywhere there was land that wasn't Antarctica.

By that moment—10000 years ago—there were perhaps 2.5 million of us on the globe. We were all then, still, as we had been since our dawn, gatherer-hunters. We had proven successful in a Darwinian sense: we had expanded into many more—indeed, into nearly all—land environments, and in so doing we had multiplied our populations at least 25-fold. But that is a very slow rate of average population growth: only 0.005% per year or 0.125% per generation during the long 60000 years of the behaviorally-modern gatherer-hunter epoch.

How ferocious was mortality to keep population growth so low? A pre-industrial nutritionally-unstressed human population with access to the technologies of settlement—building walls, roofs, and chimneys and weaving and sewing clothes—will roughly double in population every two generations. That is what the British settlers in America did in the generations after they hit the coast from Georgia to Maine. But human gatherer-hunter populations grew at an average rate of increase a rate of increase of 0.25% every two generations: two generations saw not twice as many people as its parent generation, but rather only a quarter of a percent more—one extra person for each 400. The rest had been carried off by the high mortality of the gatherer-hunter age.

Gatherer-hunter nutritional standards were adequate and diets were varied in large part because population densities were low and foraging territories relatively large. Population densities were low because mortality was ferocious. You got to watch your friends die, your spouse die, your comrades die, worst of all a large fraction of your children die, and then you died at a relatively young age.

By 10000 years ago we knew a lot more—about how to make tools, manipulate and cooperate with nature—and organize our societies to make our livelihoods, survive, and reproduce—than we had known 70000 years ago. Each band, after all, had to know about its own climate, geography, and ecology. We were able to build up our knowledge because our precious possession of language made us an anthology intelligence: what one of us knew or learned, pretty soon all who came within earshot or within earshot of someone who had once been within earshot knew. Our propensity to gossip about everything and anything is very strong, and odds are it provided a very powerful evolutionary edge. If we make truly heroic assumptions in order to construct a quantitative index of the effectiveness of our knowledge, we might guess that humans 10000 years ago collectively knew five times as much about nature, technology, and organization than their predecessors 70000 years ago had collectively known.


2.1.2. Living Standards

Even though we knew more, we did not live better. We guess that modern development economists would rate our average standard of living back in the gatherer-hunter era as the equivalent of about 3.5 dollars a day—an average economic productivity for the half of the population adult and working of something like 7 dollars a day, or 2500 dollars a year. That is not extreme poverty by today's standards: the United Nations counts extreme poverty as a living standard of less than 2 a day, and if you drop below that it becomes difficult to think about much other than how important it is to get more food and how tired even minor exertions make you.

Poor did not mean malnourished. Biomedically, our hunter-gatherer ancestors appear to have been about as healthy as we in the modern world are through early middle age—if they survived to early middle age, that is. Life expectancy at birth was twenty-five on a generous estimate. The average adult height of mesolithic—i.e., the period that ended 10,000 years ago—hunter-gatherers appears to have been about 5’8” for men and 5’5” for women, perhaps a hair less than average adult height in the rich postindustrial economies today. Our gatherer-hunter ancestors were, plausibly, better-nourished than we are today: even in the richest countries today diets are tilted toward high-caloric density carbohydrates—rice, wheat, corn, and potatoes—relative to nutritional requirements.

Thus as a gatherer-hunter you lived a well-nourished, physically-strenuous life that kept you fit. Life was also at least moderately interesting, in terms of the day-to-day cognitive puzzles that you had to solve. Gatherer-hunters avoided the mind-numbing boredom of doing the same thing over and over again to the next row of the same crop what Karl Marx called the “idiocy of rural life”, or the next item to come down the assembly line, or the next set of symbols to be copied into the next spreasheet row.

But even though life was not that of boring routinized repetitive labor, it was not what we would call comfortable: you spent a not-small part of your life hungry, cold (or too hot), or wet.

Why is it that people knew more yet lived no better 10000 years ago than 70000?


2.1.3. A Malthusian Age

To understand why the gatherer-hunter age from 70000 to 10000 years ago was one in which standards of living and productivity stagnated and in which population grew slowly, you need to keep three things in the front of your mind:

  1. that the drive to make love is one of the very strongest of all human drives,
  2. that the rate of technological and organizatonal progress from 70000 to 10000 yearw ago was, by our standards, glacial
  3. that even small gatherer-hunter population densities put pressure on resources—and worker productivity falls when resources become less abundant.

Before the coming of abundant and relatively reliable means of artificial birth control at the end of the nineteenth century, making love is followed almost invariably if not immediately by children—over a lifetime, lots of children. And once humans have children that they survive and flourish becomes the most important thing for almost every parent for two reasons:

The first reason is that you love them almost as much as and in some cases more than yourself. Recall Hektor’s prayer for his son Astyanax (a prayer that Hera and Athene worked very hard to make certain that Zeus did not grant):

Zeus, grant that this my child may be, like me, first among the Trojans. Let him be not less excellent in strength. Let him rule Ilius with his might. And may the people say of him as he comes home from battle: “He is far better than his father!”...

The second reason is that if you survive into your old age you will need someone to take care of you, and the only people likely to be willing to take care of you are your descendants. With infant and child mortality rates of 50% and life expectancies of less than thirty years, lots of pregnancies is the only way to be reasonably sure that you will have a still-living child when you go blind and toothless.

Thus human populations—back before widespread female literacy enlarged the options open to women, back before the fall in infant mortality created the expectation that your children would survive to grow up, back before widespread artificial birth control allowed women to have the number of children they wanted and not more—tended to grow until something stopped them.

A number of things can stop fertility. Perhaps celibacy and abstention from reproduction is thought of as pleasing to God. Perhaps a prospective father-in-law might tell a prospective son-in-law that marriage will be delayed until he establishes a higher status, and makes that stick. But most often and to the greatest extent that “something” is poverty: women become too skinny to reliably ovulate, and populations become to weak to harvest food in strenuous ways. As Thomas Robert Malthus was the first to see, a population subject to slow growth in technology and organization will tend to have its population grow and average productivity and living standards decline until restrained fertility and perhaps elevated mortality are just so on average that the population grows on average at the rate warranted by the growth of the stock of useful ideas. Improvements in technology and organization then lead to larger human populations, and not to higher standards of living and productivity levels, on average.


2.2. The Agrarian Age: 10000 to 500 Years Ago

2.2.1. The Neolithic Revolution and Its Consequences

Then, about 10000 years ago, comes an innovation miracle: the domestication of animals and the selective breeding of crops, and so the start of herding and of farming—the so-called Neolithic Revolution. Agriculture and herding quickly—in a couple of a thousand years—spread far. By the year -6000 farming and herding are nearly omnipresent in Eurasia and Africa, and the human population has nearly tripled, to perhaps 7 million.

Farming and herding are much more productive per unit of land than gathering and hunting. And the first few generations to adopt these technologies and social organizations experience a true bonanza. And yet when the dust settled—in the year -6000 or so—the more numerous agrarian-age humanity appeared poorer than humanity had been in the gatherer-hunter era: figure a standard of living that would be reckoned by today's development economists as roughly 2.5 rather than 3.5 dollars a day, and an average worker productivty level of not 2400 but 1800 dollars a year.

Why did these better nature-manipulation and social-organization technologies produce a poorer humanity? Somewhat paradoxically, because farm life and herding life is easier and less strenuous. Mortality is thus lower. And so, at the same living standard, population grows faster. In order to keep population growth to the rate warranted by the pace of idea invention and innovation, living standards need to fall. And the population boom from -8000 to -6000 that nearly tripled human numbers put enough scarcity pressure on natural resources to accomplish this.

A reasonable view of what we think of as “material well-being” classifies basic human needs and desires as sixfold:

  • to watch your grandchildren (or your great-nieces and nephews or your protégés) grow up,
  • to have enough food that you are not too hungry,
  • to have enough clothing that you are not too cold,
  • to have enough shelter that you are not too wet,
  • to have enough conceptual puzzles and diversions that you are not too bored, and
  • to have enough status that you can spitefully gloat (at least in private) as you incite the envy of others.

By those yardsticks, the mass of humanity in the agrarian age was worse off than in the gather-hunter age. Relative status—is, alas!, conserved: you cannot generate it from some without taking it away from others, and so there we are stuck at an equal average level no matter what the society. The upper classes in the agrarian age may well have lived better, and increasingly better, than their gatherer-hunter age predecessors. (Indeed, it is not clear what one would mean by "upper class" in a gatherer-hunter society.) But -6000 to 1500 saw no greater life expectancy than -8000. Infant and adult mortality in agrarian societies is no lower than in hunter-gatherer ones. Mortality may well be higher for adults, because plagues and famines like dense human populations. Bacteria do not care (much) if their rapid growth kills their hosts as long as that happens only after they have found a new host to jump to. Denser populations terribly vulnerable to famine, either through blight or through weather—too hot or too cold, too wet or too dry—adverse to the growth of whatever the staple happens to be.


2.2.2. Agrarian-Age Quality of Life

Dense, agarian populations become giant culture dishes for endemic debilitating diseases or periodic epidemic mortal plagues. And so population growth ceases. Generation-to-generation the population jumped up and down as the spread of agricultural techniques produced an edge in food and more children survive, as plagues and wars devastated provinces, and as bounceback takes place in the aftermath of plagues and famines that left provinces depopulated, but the survivors with large and fertile farms—which induced rapid population growth, which pushed living standards back down to 2.5 dollars a day.

An agricultural cereal-heavy diet does not contain enough iron to avoid anemia. It does not contain enough calcium to avoid tooth loss and bone weakness. Rome’s legions were paid in bread and a little salt—that’s what “salary” means. Add to this whatever meat they could find and whatever greens and seasonings they could gather, and you had the diet of the legionaries, collectively at least the most powerful group of men of their age. They wear highly-skilled practitioners of violence. They were mean. They were also short. And they were, by what we would regard as early middle age, largely toothless.

Have we mentioned endemic hookworm, tapeworm, and other parasites yet? Or that agricultural and commercial labor likely involves heavy lifting-and-carrying labor that damages your spine? Or that the relatively high population densities create greater vulnerability to infectious diseases that debilitate even when they do not kill?


2.2.3. Another Malthusian Age

Up to 1500, and even later, agricultural and commercial societies people were short. Average adult male heights of 5’3” (and adult female heights averaging 5’0” or less) appear to have been the rule for humanity once we started to farm. This indicates extraordinary malnutrition by our standards. Were we today to feed our children a diet to produce such adult heights, Alameda County Child and Protective Services would take our children away. Like the gatherer-hunter age, the agrarian age was a Malthusian age: growth in population, but not sustained permanent growth in productivity levels (outside the upper classes) or living standards, as the benefits of technological and organizational progress were offset by the pressure of population on resources.


2.2.4. Why Then the Transition to Agriculture?

Comparing the lifestyle of hunter-gatherers ten-thousand to that of illiterate peasant farmers five-hundred years ago raises an obvious question: why would people ever become farmers? Jared Diamond claims that we should—even in the United States, even today—envy our gatherer-hunter ancestors. I don’t buy this: I do not, or at least I think we should not, envy them. (He does not either: Full Professors of Physiology at UCLA and of Economics at U.C. Berkeley have chosen a life far, far removed from that of our ancestors.) But there is an important kernel here: almost all of our agricultural and commercial-era ancestors between -8000 and 1500 and even later did have good reason to envy our common pre-industrial ancestors. We understand why the transition from hunting and gathering to pre-industrial agriculture is good for those at the top of the pyramid. But why do those not at the top of the socioeconomic pyramid go along?

Most important, is that the first generation to farm—or to adopt any of the many subsequent agricultural productivity-multiplying innovations—does live the life of Riley, off the fat of the land. If you can figure out how to do it, it is good for you and your children and your chldren’s children to farm. But a well-fed and well-nourished population multiplies. So farming population densities explode far beyond hunter-gatherer densities.

Some human populations did not pursue the agricultural road. Some settled into a halfway role as nomadic or transhumant herders following their flocks on land that was, for the time and given the available biotechnology, marginal for settled agriculture. Some remained hunter-gatherers for a while. But, eventually, somebody nearby had become farmers. And the population density of the farmers grew. Hunter-gatherers rarely exceed population densities of one per square mile. Farmers on land that is good for their particular version of agricultural technology can easily support many more than a thousand in the same space. The old “forty acres and a mule” for a family of six translates into a population density of roughly 100 per square mile. When those nearby who had become farmers decided that they wanted the hunter-gatherers’ or the herdsmen’s land, they took it: numbers of 100-to-1 or 1000-to-1 are not easy to argue with.

The upshot is that—unless you were part of the rich, literate upper classes—per capita standards of living were not that much higher in 1500 as they had been back in 8000 BC. Population, however, was much greater: 500 million people in 1500, compared to 2.5 million or so back in -8000: a 50-fold multiplication in 9500 years.


2.2.5. The Pace of Agrarian-Age Progress

From -6000 to 1500 we guess that human living standards were roughly constant at perhaps 2.5 dollars a day, and worker productivity levels roughly constant at about 1800 a year as better ideas about how to manipulate nature and organize production ran up, because of increasing population, against greater resource scarcity: smaller average farm sizes and less pasture per herder. From -6000 to 1500 we guess we saw a 70-fold multiplication in human populations: an average agrarian-age rate of population growth of 0.057% per year, or 1.42% per generation. Contrast that with the gatherer-hunter era average rate of population growth of 0.005% per year, or 0.125% per generation. Technological and organizational progress was thus more than ten times as fast in the agrarian age. Why?

We guess that faster growth in the stock of useful ideas was primarily driven by three factors: settlement, literacy, and numbers.

Settlement: It isn't worth developing technologies you can't take with you; there is no built-up environment to remind you of what can be done...

Literacy: If language makes us an anthology intelligence within the band, writing makes us an anthology intelligence over space and time...

Numbers: Two heads are better than one...

Working on the other side: inequality and its consequences...

But we can only guess.


2.2.6. Grotesque Inequality within Societies


2.3. The Commercial Revolution: 500 to 250 Years Ago


2.4. The Industrial Revolution: 250 to 150 Years Ago


2.5. Modern Economic Growth: 150 Years Ago to Today


2.6. The Future?


Robert Allen and his coauthors have compiled the scanty information we have on the wages of unskilled laborers across the big cities of Eurasia from 1350 to 1900. Their wages are real wages: a value of one means that an adult male laborer employed full time, full year could earn just enough to keep his family of six or so at biological subsistence—1940 calories per adult male per day, most of it on the cheapest carbohydrate sold in that city, with only tiny amounts spent on “luxuries” (rent, wood for burning, oil, and meat). Their workers of London and Amsterdam on these budgets are eating oatmeal two meals a day, the workers of Vienna are eating rye, the workers of Delhi are eating millet, the workers of Beijing are eating sorghum, and the workers of Florence are eating polenta over and over again.

There are three subtleties of interpretation. The first is that biological subsistence is not sociological subsistence. The workers of London in 1600 did not spend 1/3 of their income on “necessities” and have two-thirds left over for luxuries, for they did not want to eat oatmeal two meals a day and in fact did not eat oatmeal two meals a day. Oats were, as famously defined by Samuel Johnson, “a grain that in England is fed to horses and in Scotland is fed to men.” The Scots had a reply—“That is the reason that England breeds such fine horses, and Scotland breeds such fine men.” But an English laborer of 1600 would have been as humiliated to be forced by penury to eat like a Scotsman—oatmeal—as a Republican member of the U.S. House of Representatives in 2003 would have been as humiliated to be forced to eat French fries.

The second is that these wage level calculations assume that you could have found work all the time, which seasonal labor requirement patterns and commercial and political disruptions made chancy at best.

The third is that these are the wages that were paid to urban workers hired for the day. These are the wages of those whose connections with their employers were overwhelmingly short-term cash-nexus connections. Such people are not in general representative of society as a whole even today, and were definitely not in general representative back in the past. In rapidly-growing cities like fourteenth-century Florence, fifteenth-century Vienna, sixteenth-century Amsterdam, seventeenth-century Delhi, or eighteenth-century London, the day laborers were people from the countryside pulled into the city by the chance to make extra bucks who sell their labor-power to employers who see opportunity and don’t have enough in the way of serfs or apprentices or liegemen to handle the workload. In cities like nineteenth-century Delhi, Beijing, or Florence, the urban day laborers were people who have been pushed out of the countryside by the lack of land or a place and have washed up on the shores of the city to live by their wits or starve. Italy in 1850 was not a country in which the average person subsisted on 1600 calories of polenta per adult male equivalent per day.

That said, the pattern that Allen et al. paint is clear and convincing. They pick up the story in the aftermath of the Black Death of the mid-fourteenth century—the bubonic plague. With the population of Europe down by between a quarter and a half from its early fourteenth-century medieval high, larger farm sizes produced an agricultural bonanza for peasants who could (a) produce more and (b) bargain for lower feudal rents from an Earl of Pembroke desperate to have somebody working the land to pay something. Urban plague mortality had been highest. City employers were thus desperate to pay through the nose, and urban unskilled day laborers typically earned three times the biological “subsistence” family wage.

By 1600, however, Allen et al. find that urban unskilled day-laborer real wages are much lower. Italy and Austria have filled up with people, farm sizes are smaller, and the shift of trade from the Mediterranean to the Atlantic has advantage Amsterdam and London at the expense of Florence. Neither Florence nor Vienna was anymore a good place to be an unskilled day laborer and try to raise a family. Allen et al. do, however, pick up early-Moghul Delhi, which then looked a lot like London: a rapidly-growing capital city in a rich agricultural region that benefited from the global trade-war-and-conquest boom set off by the invention of the sea-going caravel and the voyages of Christopher Colombus and Vasco da Gama. And by the eighteenth century Delhi has joined Florence, Vienna—and mid-Qing Beijing—as places where the lot of a masterless man trying to raise a family was very bad indeed. And we think that this roughly tracks what was going on in the countryside as well: people were still on net moving from the countryside to Florence, Vienna, Delhi, and Beijing, which means that the lot of a youngest son or of someone whose lineage had lost out in a dispute over land ownership out in the countryside was even worse.

London and Amsterdam are the only cities in Allen et al.’s dataset that managed to avoid the dismal Malthusian fate. Their workers did not have to subsist on oatmeal year-in year-out (or millet, or sorghum, or polenta) but due to the commercial-revolution expansion of the world trading economy plus a little successful imperialism could eat bread instead of oatmeal, buy beef and beer on a regular basis, wear better clothes, purchase stimulants like sugar and tea, and even—after the Protestant Reformation which made literacy a duty because reading the Bible was storing up treasure in heaven—books.



Doron M. Behar et al. (2008): The Dawn of Human Matrilineal Diversity https://web.archive.org/web/20080430222448/http://www.ajhg.org/AJHG/fulltext/S0002-9297(08)00255-3
John Hawks (2008): Did Humans Face Extinction 70,000 Years Ago? http://johnhawks.net/weblog/reviews/genetics/mtdna_migrations/sub-saharan-africa-population-size-behar-2008.html
Karl Marx and Friedrich Engels (1848): Manifesto of the Communist Party


3. East African Plains Ape

The ancestors of us East African Plains Apes diverged from the chimpanizee lineage about six million years ago.

Chimpanzees... have fission-fusion societies, in which subgroups form and reform within a larger, more stable community.... Males spend their lives in the community they were born in, while females transfer out of their natal community to a new community when they reach sexual maturity. In both species, females commonly mate with many males over the course of an estrus cycle.... Intergroup warfare and group extinction are general features of chimpanzee life. Chimpanzees.... hairy... sexually promiscuous, but they now look less like hippies and more like bikers. Really scary bikers....

Stone tools date... back [at least] to the Oldowan, 2.6 million years ago.... Tool making is not uniquely human. (For tool use in dinosaurs, see here.) But Oldowan tools–including choppers (below), pounders, and scrapers—go beyond anything chimpanzees, or other animals, do.... Early hominins could have dramatically increased available food energy by pounding vegetables and chopping up meat into more digestible pieces. Tool use may have been an early step in our ancestors’ move to high energy diets. Meat-eating began to be important in human evolution around 2.6 million years ago. Somewhat later we see evidence that some hominins have lighter jaws and aren’t chewing as much....

From around 1.4 million years ago, Acheulean hand axes appear in Africa. They will eventually show up in southwest Europe and as far east as India. Hand axes were long thought to be absent from further east, but now have been found sporadically in East Asia. (Bamboo might have been an alternative to stone in the east.) Wear analyses show that hand axes, “the Swiss Army knife of the Paleolithic,” were used for a variety of purposes: cutting wood, slicing meat, scraping hides.

The hand axe implies a great leap forward cognitively from earlier Oldowan tools (although you can flay an elephant with Oldowan flakes). People (let’s call them people) were not just choosing the right material and making the right hand movements, but choosing the right shape of stone, and imagining the hand axe inside it before they started.

Dietrich Stout, an experimental anthropologist at Emory University, has trained students to make modern-day Acheulean handaxes, and monitored their brains as they learn....


Sophisticated tools like the Acheulean hand axe probably tell us something not just about cognition in relation to tool making, but also about social cognition. You wouldn’t make a hand axe, use it, and abandon it. Nor would you go to all the trouble if the biggest, baddest guy in the group was immediately going to grab it from you. So there is probably some notion of artifacts-as-personal-possessions by the time Acheulean appears.

Possession is a social relationship, a relationship between two or more individuals with respect to the thing possessed. Robinson Crusoe didn’t “own” anything on his island before Friday came along.

Linguists have noted something interesting about the language of possession that maybe tells us something about the psychology of possession: Expressions for possession are often similar to expressions for spatial locations. Compare spatial expressions: João went to Recife; Chico stayed in Rio; the gang kept Zezinho in Salvador; and corresponding constructions for possessions: the Crampden estate went to Reginald; the Hampden estate stayed with Lionel; thag kept axe. Of course the Crampden estate didn’t go anywhere in physical space, but it still traveled in the abstract social space of possession. In some cases just switching from inanimate to animate subject will switch the meaning from locative to possessive. The Russian preposition y means at/near when applied to a place (People are at Nevsky street) but possession when applied to a person (Hat is “at” Ivan = Ivan has hat.)

What may be going on here: people (and many other creatures) have some mental machinery for thinking about physical space. That machinery gets retooled/borrowed/exapted for thinking about more abstract relationships. So the cognitive psychology of space gets retooled for thinking about close and distant social relationships, or time ahead and behind. In other words, we may be seeing a common evolutionary phenomenon of organs evolved for one purpose being put to another purpose–reptile jaw bones evolve into mammalian inner ear bones, dinosaur forelimbs evolve into bird wings. You can find Steve Pinker making this argument in his book The Stuff of Thought. And Barbara Tversky’s just-published Mind in Motion: How Action Shapes Thought seems to make the argument at greater length; I’m looking forward to reading it. For a while most of the evidence of repurposing spatial cognition for more abstract relationships came from linguistics, but there’s now some corroboration from neurology.

And I’ve made the argument for the particular case of kinship: regularities in kin terminology across cultures tell us something about pan-human ideas of “kinship space.” (My kin and mybody parts are arguably the most basic, intrinsic primitive sorts of possessions, since long before my handaxe.) This implies that the evolutionary psychology of kinship has not just an adaptive component (adaptations for calculating coefficients of relatedness and inbreeding), but also a phylogenetic component (homologies with the cognitive psychology of space). We’ll see other possible examples, involving e.g. the evolution of speech sounds, as we move along....

one of the great human distinctions is that we alone use fire. Fire is recognized as something special not just by scientists, but in the many myths about how humans acquired fire. (It ain’t just Prometheus.) Claude Lévi-Strauss got a whole book out of analyzing South American Indian myths of how the distinction between raw and cooked separates nature from culture. (I admit this is where I get bogged down on Lévi-Strauss.)

Until recently the story about fire was that it came late, toward the latter days of Homo erectus. But Richard Wrangham, a primatologist at Harvard, turned this around with his book Catching Fire (which is not the same as this book), arguing that the taming of fire goes back much earlier, to the origin of Homo erectus. Wrangham argues that it was cooking in particular that set us on the road to humanity. Cooking allows human beings to extract much more of energy from foods (in addition to killing parasites). Homo erectus had smaller teeth and jaw than earlier hominins and probably a smaller gut, and it may have been fire that made this possible. Cooking is also likely to have affected social life, by focusing eating and socializing around a central place. (E O Wilson thinks that home sites favored intense sociality in both social insects and humans.)

Surviving on raw food is difficult for people in a modern high-tech environment and probably impossible for people in traditional settings. Anthropologists are always looking for human universals, and almost always finding exceptions (e.g. the vast majority of societies avoid regular brother-sister marriage, but there are a few exceptions, including Roman Egypt and Zoroastrian Iran). But cooking seems to be a real, true universal. No society is known where people got by without cooking. Tasmanians, isolated from the rest of the world for 10,000 years, with the simplest technology of any people in recent history, had lost the art of making fire, but still kept fires going and still cooked.

Recent archeological finds have pushed the date for controlled use of fire back to 1 million years ago (see today’s tweet on Wonderwerk cave), but not all the way back to the origin of Homo erectus. This doesn’t mean Wrangham is wrong. Fire sites don’t always preserve very well: we have virtually no archeological evidence of the first Americans controlling fire, but nobody doubts they were doing it. It could be that it will be the geneticists who will settle this one. The Maillard (or browning) reaction that gives cooked meat much of its flavor generates compounds that are toxic to many mammals but not (or not so much) to us. At some point we may learn just how far back genetic adaptations to eating cooked food go.

An alternative to an early date for fire, there is the recent theory that processing food, by chopping it up and mashing it with stone tools, was the crucial early adaptation.

Whenever it is exactly that humans started cooking, the date falls in (Northern hemisphere) grilling season on Logarithmic History, so you can celebrate the taming of fire accordingly. It doesn’t have to be meat you grill. Some anthropologists think cooking veggies was even more important. I recommend sliced eggplant particularly, brushed with olive oil to keep it from sticking, and with salt, pepper, and any other spices....

Human beings have an absolutely outsize impact on the Earth, and the advent of human beings looks like one of the major evolutionary transitions, comparable in importance to the origin of the eukaryotic cell or multicellular life. But even if we buy this, it still leaves open the question of whether there’s a key adaptation – a One Weird Trick – that accounts for the exceptional course of human evolution. Here are some candidates that being are being batted around these days:

1) The cognitive niche. The basic idea is at least as old as Aristotle, that human brings are defined by their capacity for Reason. A modern version of this is advocated by evolutionary psychologist John Tooby and cognitive scientist Steven Pinker. Pinker in particular has elaborated the argument that humans are uniquely adapted to acquire and share knowledge, by virtue of a suite of cognitive, social, and linguistic adaptations. We’ve already touched on several aspects of this: Human beings seem to have taken the capacity for thinking about physical space and retooled it for thinking about the abstract cognitive space of possession – a social relationship. (Other abstract cognitive spaces include kinship, time, and change-of-state.) And humans seem to harness the machinery for processing the sounds of interacting solid objects in creating major categories of phonemes. For a more complete exposition, here’s an academic article by Pinker, and a talk on youtube.

2) Culture. Rob Boyd and Pete Richerson, who’ve done a lot of mathematical modeling of cultural evolution, are skeptical about the “cognitive niche” argument. Too much culture, they argue, is things that have been learned by trial-and-error, and are passed on from one generation to the next without people understanding why they work. Boyd and Richerson appeal, as anthropologists have for generations, to the importance of culture. We mentioned earlier their argument that the frequency of climate change in the Ice Age was nicely calibrated to favor social learning rather than individual learning or instinct. Joseph Henrich provides a recent defense of the importance of culture. Contra Pinker, he thinks humans often don’t have a good cause-and-effect understanding of the things they do, but depend heavily on imitation and the accumulated wisdom of the elders. And see this post, for the importance of High Fidelity cultural transmission in the evolution of animal and human intelligence.

3) Recursion. What if you have one mirror facing a second mirror, so the first mirror shows what’s in the second mirror, which shows what’s in the first mirror …? What if you take a chameleon, which tries to take on the color of its surroundings, and put it on a mirror? What if you point a video camera at the very screen that’s showing what the video camera is pointing at? What if (getting mathematical) you use a function in defining that same function? What if you use the cleaning attachment from your vacuum cleaner to suck dust off the vacuum cleaner itself? (Okay, the last one is a bit lame.) The basic idea in each of these cases is called recursion, which is a major concept in mathematics and computer science. Douglas Hofstadter’s Gödel, Escher, Bach is all about recursion. Some people think recursion – nesting ideas about ideas inside one another in a potentially infinite hierarchy, or (for syntax) phrases inside phrases — is central to human uniqueness. Noam Chomsky has lately been pushing a hard-core version of this argument. Here he is with Robert Berwick defending his view.

Related to the idea of recursion is the idea of “meta-representation”: not just having ideas about the world but having ideas about ideas, being able to put a box around a proposition, and then attaching a tag to it that says the equivalent of “This is true” or “This is false” or “This will be true later” or “Suppose this were true,” and then manipulating it accordingly. A nice little essay in “imagination,” elaborating this idea, is here from Simon Baron-Cohen, best known as an authority on autism.

4) Shared intentionality. Suppose you and I are friends with a couple, Fred and Wendy Smith. I tell you “I saw Wendy Smith kissing a man in the park yesterday.” Logically speaking, there’s nothing to say the man wasn’t Fred. But you’ll probably assume that I meant she was kissing someone other than Fred. Why? Well if the man had been Fred I could just as easily have said “I saw Wendy Smith kissing Fred in the park yesterday.” Since I didn’t say that, you assume I mean to convey the man wasn’t Fred. Note this only works if both of us try to pack as much relevant information into our sentences as possible and know the other person is doing the same. (If you think this sounds like recursion, you’re right.) Back in the 1950s, Paul Grice, a philosopher, worked out a lot of how we pack non-literal meanings into sentences. But the same principles are at work even when people are communicating non-linguistically. This leads to another theory of human uniqueness: human beings are uniquely good at developing shared intentions with one another: each party knows the other party is trying to communicate something, so they converge on the correct answer. People may have been doing this even before language evolved. Following up on this can quickly get you into game theory, where a central concept is “common knowledge”: not just “I know X” and “You know X,” but “I know X,” and “I know X is common knowledge to us,” and similarly for you. The cc option on your email generates common knowledge: if you see someone’s address there then they see yours, and you know they know you know, etc. Here’s a philosophical treatment.

scleraBut you can skip the philosophy if you want and move on to a telling little piece of anatomy that’s relevant here. In most mammals, including chimpanzees, the sclera (white of the eyes) is not visible. It’s hard to tell where a chimpanzee is looking, easy for a human. Human eyes make it easy to cooperate in sharing attention, a first step in developing shared intentions. If you know your card games, chimpanzees are playing poker, humans are playing bridge.

Our discussion of human uniqueness on Logarithmic History has been frustratingly short on specific dates. But human sclera are probably a fairly simple trait genetically, and we may soon enough discover the genes involved and even tell how long ago they mutated....

It’s fancy dress day on Logarithmic History. Between 170 and 80 thousand years ago, people started wearing clothes. We know this from recent genetic studies showing that sometime during that period, probably closer to 170 kya, pubic lice and body (=clothing) lice diverged into two separate species. This is before the major exodus of modern humans from Africa, so it may mean clothing was not just about protection from high latitude winters. Or else Neanderthals or Denisovans were wearing clothes, and we got body lice from them. (There’s an even earlier split, three million years ago, between head lice and pubic lice, that probably means human ancestors had lost their fur. And there’s another story about the ancestors of East Asians picking up a different strain of head lice from non-sapiens humans that we may cover later.)

Lice are not just disgusting, but dangerous. On later dates, we’ll have occasion to see how louse-borne diseases like typhus have affected the course of history. But for now let’s forget about lice, and celebrate clothing, with Irving Berlin’s song about fancy duds, “Puttin’ On the Ritz,” covered below by a Moscow flashmob.

Also relevant to the video is Merlin Donald’s book Origins of the Modern Mind: Three Stages in the Evolution of Culture and Cognition arguing that dance is part of a mimetic mode of culture that came before language. And Barbara Ehrenreich’s book on dancing in history and prehistory Dancing in the Streets: A History of Collective Joy. is worth a look....

Our genus, Homo, left Africa by 1.8 million years ago. On the latest genetic evidence, there was another Out Of Africa migration about 700,000 years ago, which led to the ancestors of Neanderthals and Denisovans splitting off from the ancestors of Homo sapiens (who stayed in Africa this time), and replacing Homo erectus in Eurasia. And there seems to have been another Out Of Africa migration around 200,000 years ago that introduced early Homo sapiens mitochondrial DNA into the Neanderthal gene pool. This early migration didn’t lead to major evolutionary change, however. Other Neanderthal genes (i.e. nuclear rather than mitochondrial DNA) show no evidence of it.

More consequential was another Out Of Africa migration by Homo sapiens around 120,000 years ago. This skull dates back to then. skhul5 Skhul 5 was found back in 1935, in Israel, on the slopes of Mount Carmel, buried together with a boar mandible. It looked for a long time like the skull came late in the day, and might represent a transition from Neanderthals to Homo sapiens. But now that date has been moved back, thanks to the development of new dating techniques (thermoluminescence, electron spin resonance) that finally broke the 40,000 year limit for Carbon 14. Skhul 5 now looks like a representative of an early movement of Homo sapiens out of Africa. But the skull also has some Neandethal-like features (check out the “Neanderthal bun” at the back of the skull) and could have hybrid ancestry.

Until recently it looked like this and other very early Homo sapiens outside Africa were a side branch that left no descendants – think Leif Erickson, not Columbus – with the real move coming later. But recently there has been a recalibration of DNA mutation rates that suggests that the split between African and non-African branches of H. sapiens happened closer to 100,000 years ago than 50,000 years ago. And there have been discoveries of stone tools with African affinities in the Arabian Peninsula, in the United Arab Emirates (Jebel Faya, 125 kya) and Oman (106 kya). It may be that when Homo sapiens left Africa 125,000 years ago (perhaps across the Red Sea to Arabia, rather than across the Sinai), they spent a long time isolated in a corner of Southwest Asia before much later expanding more widely.

It’s even possible that more dramatic revisions of the Out Of Africa story will be called for in the future. It could be that the finishing touches in the evolution of modern Homo sapiens happened in North Africa or Southwest Asia, with the genes involved spreading to Sub-Saharan Africa by back migration....

The period between the time Homo sapiens leaves Africa 120 thousand years ago, and the time when H. sapiens spreads far and wide through Eurasia, replacing Neanderthals and others, 45 thousand years ago, sees episodes of increasing cultural complexity in Africa. One of these occurs at Blombos cave, at the southern tip of South Africa. There, over tens of thousands of years, people make a cultural great leap forward. blombos2 75 thousand years ago, we find that they produce finely crafted stone blades that are part of multi-part composite tools. They make shell ornaments.


And they etch ocher (a red stone useful as a dye, but not for tools).

Oddly though, this tradition doesn’t last. It’s over by 60 thousand years ago. It may be that people left as climate deteriorated. But Blombos cave is a reminder that cultural progress is not always a permanent thing. It looks like an early instance of Rise and Fall: a culture rises to new heights, and then falls back....

74 thousand years ago, a big chunk of the island of Sumatra blew up. It was the biggest volcanic explosion in the past two million years, expelling 2800 times as much debris as the Mount Saint Helens eruption in Washington State in 1980. Ash from the super-eruption is found all the way from Lake Malawi to the South China Sea. The resulting Toba caldera measures about 20 by 60 miles.


The Toba eruption coincides with a shift back to glacial conditions, and it may be that there’s a connection, that Earth went through a long volcanic winter after the eruption, which shifted climate to a colder equilibrium.

Did Toba have an effect on human evolution? Somewhere between 100 and 50 thousand years ago, human populations went through a bottleneck: modern humans are descended from just 1,000 to 10,000 breeding pairs from that period. It’s been argued that Toba wiped out the majority of Homo sapiens around at the time, leaving only a small group of survivors.

But the evidence that Toba is responsible for the bottleneck is equivocal. In some places humans seem to have passed through the period of the eruption without major disruptions. Also, there’s a point that gets missed in a lot of popular reporting: just because a species went through a bottleneck doesn’t necessarily mean that the population of the whole species ever shrank to that size. In the case of Homo sapiens it could be that the total population was always many times larger than 1,000-10,000. It’s just that the other tens or hundreds of thousands got replaced. In other words, we may not be looking at an external catastrophe wiping out most of humanity, and a few groups of survivors recovering. Instead, we may be looking at a small population of our eventual ancestors expanding and outcompeting other populations, so that it was our ancestors, not a volcano, who made sure that most human beings alive 74,000 years ago didn’t leave descendants.


This may reflect something special about human evolution: human beings typically belong to tribes and ethnic groups defined by distinctive cultures, and cultural boundaries (including language boundaries) often act as barriers to interbreeding. Several authors have suggested that this may make human beings unusually susceptible to population replacement via “cultural group selection,” and that this might account for humans having unusually low effective population size, as genes “hitchhike” along with expanding cultures. Interestingly, sperm whales, which live in populations defined by different song dialects (and other cultural differences) may show the same genetic pattern. And here’s me on kin selection and ethnic group selection, related....

Human language is probably more than One Weird Trick. It’s multiple weird tricks. We’ve already posted about phonemes, and how they can be strung together to make words. That’s (at least) one trick. And then words are strung together to make phrases and sentences: but there are a multiple weird tricks here as well. Consider this quotation from some language researchers:

Every human language sentence is composed of two layers of meaning: a lexical structure that contains the lexical meaning, and an expression structure that is composed of function elements that give shape to the expression. In the question, Did John eat pizza?, the lexical layer is composed of the words John, eat, pizza … The sentence also contains did, which has two functions: it marks tense, and by occurring at the head of the sentence, it also signifies a question. (Miyagawa et. al.) The lexical level of language includes content words: nouns, most verbs, adjectives. The expressive level contains functional words (auxiliary verbs, conjunctions, articles, and so on), as well as tenses and other inflections, and even functional operations like moving around the parts of a phrase. We can think of a sentence like a piece of carpentry, a bookshelf, say. A typical bookshelf will consist of the parts that hold things up (shelves, sides, etc., analogous to lexical structure), and parts that fasten these parts together (dowels, screws, bolts, nuts, nails, glue, etc., analogous to expressive structure). bookshelf1 So language gets its open-ended expressive power by fastening together expressive and functional constructions in (more-or-less) alternating levels. Here’s an illustration, a Christmas tree of a phrase with expressive levels in green and functional levels in red:

language tree

But there are other ways to build furniture. For example, here’s a desk with no fasteners. Instead, the load bearing parts have slots and tabs that fit together. This is simpler but less flexible than having boards and fasteners that you can put together however you see fit. bookshelf2

The analogy with language would be a protolanguage with nothing but content words – nouns, verbs, and adjectives, say – and lexical structure. The analogy works because verbs come with built in slots that nouns can fit into, even without any extra “fasteners” to hold them together. Linguists call this the “argument structure” of a verb. (Think about functions and their arguments if you’re into math or computer science.) For example fear and frighten are both transitive verbs, but they have different argument structures

Carg fear thunder. Thunder frighten Carg. In one case the experiencer goes in the subject slot, and the agent goes in the direct object slot. In the other case it’s the reverse. Some verbs, like burn, have more than one argument structure.

Carg burn meat. Meat burn. English verbs have some tens of different argument structures. (Note that I haven’t put any tense on the verbs. That would be part of expressive structure, which we’re leaving off here.)

So a protolanguage, one step along the way to a full blown language, could consist of a bunch of verbs and their argument structures, together with nouns slotted in the appropriate spaces as needed, and adjectives added to convey additional information. Is this what Neanderthal language was like? There is evidence that Neanderthal ancestors as far back as 430,000 years had hearing specialized for the frequencies of speech. (This is not the case with chimpanzees, or earlier hominins.) But we don’t know yet how complex Neanderthal speech was. Eventually, as we figure out the genetics of language, we’ll find out. For now though, let’s make today – just about the last day on Logarithmic History that Neanderthals are around – “Talk Like a Neanderthal Day.”

Carg publish blogpost now. Carg sleep. Goodbye!...

Why do humans have such big brains? Partly because we’re primates, and primates in general have big brains – not just big brains but an exceptional density of neurons, especially in big primates. But a recent article by González-Forero and Gardner offers some more specific ideas.

Before getting down to the article, a general reflection on statistics and methodology:

In many areas of science, you’ve got a lot of data and you want to sort out cause and effect. This happens in evolutionary biology, for example, when you want to determine what selective pressures have caused brains to evolve to different sizes. And it happens in medicine, when you want to find out what lifestyle choices generate what health problems. It also happens in social science and public policy, when you want to find out what programs generate what social outcomes. A common method in these cases is to use multivariate regression, looking for the strongest correlates of your dependent variable. This has its limits however. You often find that a lot of your variables are correlated with one another, and it’s hard to figure out what is cause and what’s effect.

So there’s been a lot of interest lately in a different approach, where you start out at the beginning with an explicit model of cause-and-effect pathways and use your data to estimate the strength of causal connections. An excellent popular introduction to this rapidly developing field comes from Judea Pearl, in The Book of Why: The New Science of Cause and Effect. Pearl makes the case here that statistics needs to move beyond pattern recognition, to testing causal models and counterfactual reasoning. Pearl sees counterfactual reasoning in particular as a human specialty, One Weird Trick that distinguishes humans from other creatures, and he is skeptical about current work in Artificial Intelligence, impressive as it is, that is mainly about pattern recognition.

Richard McElreath, commenting on González-Forero and Gardner, puts it this way:

“Automobile engineering can provide an analogy for studying this type of system. It would be difficult to understand racing-car design through regression analysis of how engine size varies depending on changes in other features, such as the mass and shape of the car. Instead, a model is needed that uses physical laws to predict optimal combinations of the variables under different criteria. Understanding brain evolution poses a similar challenge in that an organism’s features co-evolve under biological constraints.” So turning to the article itself, what the authors do is to test an explicit model in which a developing organism has to allocate energy to growing a brain, growing a body, and reproducing. They ask what sorts of evolutionary challenges would lead to the particular combination of brain size, body size, and reproductive life history that we see in Homo sapiens. The challenges might be ecological (e.g. securing more food). They might be social (outwitting competitors). They might be solitary or cooperative (working with others to secure more food, or banding with others to defeat rival bands). Their conclusion: the best fit to their model comes when they assume that the evolution of big brains is 60% a result of individual ecological adaptation, 30% a result of cooperative ecological adaptation, and 10% a result of group-versus-group social adaptation. More specifically, what mostly drives the evolution of brain size in their model is that marginal returns to investing in ecological skills don’t decline as quickly for humans as for our close relatives. Spending extra years learning stuff continues to have a payoff for us, maybe because culture and language mean that there are a lot more useful tricks floating around to learn.

These results have to be considered pretty tentative at this point. Note however that they count strongly against the view that human brain evolution is mostly about being Machiavellian and outsmarting the other guys, although they do allow a modest role for inter-group competition. And they count against the view, advocated by Geoffrey Miller, that the human mind evolved as a sexual display, like the peacock’s tail. So it may be true that “sexual love … lays claim to half the powers and thoughts of the youngest portion of mankind” (Schopenhauer). But (at least according to González-Forero and Gardner), whatever the claims of love on our hearts, we owe our big brains to our work....

28,000 years ago

The Venus of Willendorf, from Austria, is one of a number of “Venus figurines” from the European Upper Paleolithic.


The statuette is realistic, except for the attenuated/missing hands and feet, and the absence of facial features. Obviously she’s nude, and fat. But not entirely unclothed. The pattern on her head is not just an abstract design, but carefully depicted piece of headgear.


It took a woman, archeologist Olga Soffer, to notice that this figurine represents not just a naked woman, but a fashion statement. Here’s a quotation:

A close examination of this specimen shows a spirally or radially hand‐woven item which may be initiated by a knotted center in the manner of some kinds of coiled baskets. The technique represented is a two‐element structure in which an apparently flexible, horizontal foundation element or warp is vertically wrapped with stem stitches. The foundation element is clearly visible between the stitches, some of which are plain while others are countered. Work direction is right to left, and at least seven circuits encircle the head, with two extra half‐circuits over the nape of the neck. The selvage, as depicted over the forehead, simply has the wrapping element encircling the final horizontal warp circuit. Several areas on the body of the cap appear to illustrate splices, where new material has been added. Many other Venus figurines are also nude but adorned – with headgear, or with bands and belts, or with skirts, sometimes worn, gangsta style, below the buttocks. These figures tell us something about the complexity of textile technology long ago. What more is going on – whether we’re seeing a representation of mythology, of a beauty pageant, or an initiation rite, or all of the above – is a mystery....

In July and August, this blog covered one of the great revolutions in information transmission, the evolution of language. And as we move into September, we will consider another, the invention of writing. But in between these two great revolutions, there are tantalizing hints that people were experimenting with other techniques for enhancing social memory.

Genevieve von Petzinger has made an extensive study of cave paintings from Ice Age Europe, 40,000 to 10,000 years ago; her results are presented in a recent book. The most famous cave paintings are pictures, sometimes of extraordinary quality. But von Petzinger has been interested in something else, in the geometric signs that often accompany these paintings, or stand on their own. These are not random doodles. A limited number of different signs – she lists just thirty two – is found repeatedly. Some signs, like the Spanish Tectiform, are limited in geographic distribution. Some appear early and disappear later, some do the reverse, others persist through the whole period.

ice age signs

These signs would seem to be some kind of symbolic code. But not, yet, a writing system. Perhaps some of them represent astronomical phenomena, like modern astrological symbols:

astrological signs

or perhaps they represent the terrestrial natural world, or social divisions, or all of the above. At this point we don’t know....

14.6-13.8 thousand years ago (posted a day late).

The last glacial phase looks like it’s coming to an end, and people in the Natufian culture of the Levant look like they’re gearing up to invent agriculture. They’ve settled in villages, and are harvesting and storing grain, but not yet sowing it. Possibly they’re brewing beer for feasts. This turns out to be a false start though. In a thousand years or so the glaciers will come back for a final hurrah (the Younger Dryas event), and only after this will farming actually get going.

If you plug different frequencies of different genes from a bunch of populations into a computer and ask it to generate a tree where genetically similar populations share closer branches, you get something like this:

cavalli-sforza tree

This is from the pioneering synthesis of genetics by Cavali-Sforza and co-workers, back in 1994. This looks like a nice diagram of humans spreading out of Africa, maybe some taking a southern route (the Southeast Asian branch), and others a northern route (North Eurasian), and I used to teach it this way in anthropology classes. But as we look at ancient DNA, we’re finding that things are more complicated. Even 14,000 years ago, the structure of populations is different from what we’re used to today. We’ve already mentioned the Ancestral North Eurasians earlier, who just maybe could have spoken a language ancestral to Greenberg’s Eurasiatic family.

In the Near East, too, things were complicated. A paper out recently shows that there were three very different hunting and gathering populations in Anatolia, Western Iran, and the Levant. Folks in Iran and the Levant were as genetically distinct as modern Europeans and Chinese! Either the Near East during this period had just been settled by migrants from widely separated places, or there had been strong barriers to gene flow in place for some time. Since then people in the area have mixed a lot.

Each of these populations of hunters and gatherers will give rise to its own set of farmers. The Natufians will contribute a lot to the ancestry of later farmers in the Levant. And apparently each set of farmers will send migrants off in a different direction: the Anatolians to Europe, the Iranians (or some Caucasian relatives) to the Eurasian steppe, and the Levantines to East Africa. It’s possible that the Natufians were speakers of a language ancestral to the Afro-Asiatic family, one of the oldest widely accepted language families, including Arabic and Hebrew, Somali and Oromo....

13.8-13.1 thousand years ago

For a long time the Clovis culture, associated with these spear points found across North America, looked like the earliest evidence of human occupation of the Americas. Clovis people are often thought to have entered the continent through an ice-free corridor that opened up between glaciers in Western Canada (although there are other possibilities).


But we now know that there were people in the Americas before Clovis. The Monte Verde site in Chile, dating more than a thousand years earlier (tweeted earlier) is the best evidence. And just in the past few years, we’ve learned something about the genetics involved. Modern Amerindians are overwhelmingly a mixture of East Asian and Ancestral North Eurasian ancestry. But a small fraction of their ancestry is something else: it connects them with some relict populations in Southeast Asia and Melanesia. (In current Southeast Asia these populations have been pushed aside by later arrivals.) The best current explanation for this pattern is that an early population traveled along the Pacific Coast all the way from Southeast Asia to Chile by 15 thousand years ago, when the inland route was still blocked by ice. When Clovis and related peoples made their way to the New World, these early migrants were largely replaced, but left behind a trace of their ancestry.

There’s actually some linguistic work that’s consistent with the genetics. Johanna Nichols is a linguist who has identified various linguistic strata in the New World. These are not the same as language families. Think of it this way: the Khoi-San languages of Africa are famous for their click sounds. These languages, spoken by Bushmen and other isolated hunting and gathering groups, may be extinct before the century is out. But click sounds have been borrowed by some of the Bantu neighbors of these groups. While these non-Khoi-San click speakers do not constitute a language family, they do tell us something about pre-Bantu language history.

Nichols finds a far-flung linguistic stratum distinguished by a large number of otherwise rare features, in both Melanesia and southern South America. We might compare Nichols work on linguistic strata with Greenberg’s work on Eurasiatic. The two use different methods. Both are intensely controversial within linguistics. But in both cases, it looks like distant geographical affinities proposed by linguists get support from the latest genetic research. (We’ll be getting to more generally accepted language families later this month on Logarithmic History.)...

The Clovis culture lasts less than half a millennium. But it coincides with a major change in the North and South American fauna: specifically with a wave of extinctions of large animals. We’ve seen something like this before with the human settlement of Australia. There’s still controversy about the causes, but it seems likely that humans played a major role in both extinctions, even if climate change also mattered.

The mass extinctions caused by humans differ significantly from the five generally recognized earlier mass extinctions, which mostly seem to have resulted from physical disasters, like asteroid strikes and poisonous gases. A better analogy for human mass extinctions might be found all the way back at the beginning of the Cambrian period, 540 million years ago. Then, a relatively low-key, more-or-less predator-free fauna (the Ediacaran fauna) faced a devastating challenge from newly evolved, mobile, visually guided predators. The Human Revolution may come to rival the Cambrian Revolution in its biotic consequences....

You’ve probably heard the news – by now it’s pretty old news – that there is more genetic variation within human populations than between them. More specifically, we can say that averaging across the whole genome, a typical human being will look like they get about 85% of their ancestry from a gene pool they share with all humanity, about 10% from a gene pool specific to a continent-scale race (East Asian, Sub-Saharan African, or whatever), and about another 5% from a localized gene pool (Japanese, Yoruba, or whatever).

This is an interesting statistic. It mostly reflects the fact that different human populations haven’t been diverging for very long (in evolutionary terms). Plus there have been episodes of gene exchange after the initial Out of Africa divergence.

But the statistic is also misleading. It holds for the genome as a whole, where it looks like most genes have not been under strong selection. But the subset of genes that has been under strong selection can differ a lot more between populations. (Slightly off-topic: this is why you can’t plug the numbers for ethnic genetic similarity into the formula for kin selection, and make predictions about ethnic nepotism. See here for a blog post, and here for an article.)

A case in point is the EDAR gene, which encodes a protein active in ectodermal tissues like skin. Somewhere in East Asia around 30,000 years ago, a point mutation occurred in this gene, a single nucleotide substitution. The mutant allele spread rapidly, and is now found in most of East Asians and New World Indians. The population that entered the Americas must have been at or near fixation for the new version of the gene. This rate of spread is far too great to be accounted for by genetic drift. The mutant must have had some selective advantage.

edar Frequency of old (blue) and new (red) EDAR alleles

Charles Darwin thought that the main selective force driving the divergence of human populations was sexual selection. Different groups developed different standards of beauty, and selected mates accordingly. (Here’s an article arguing that culturally transmitted aesthetic standards can drive particularly rapid divergence.) In support of this, we observe that some of the greatest differences across populations, with zero overlap between some pairs of populations, are in readily visible, esthetically charged traits like skin color and hair form.

The EDAR gene acts on physical appearance: it affects hair growth. Carriers of the mutant version have thicker hair shafts, and their hair grows out straight, not wavy or curly. So perhaps sexual selection for thick tresses contributed to the spread of the gene. But before we get carried away with that theory, we should note that the mutant version has several other effects. It causes incisors to develop with a characteristic “shoveled” shape. It results in more numerous sweat glands. It also affects mammary glands, leading to less mammary tissue, but a denser network of ducts to carry milk. A recent article argues that it was differences in survival among nursing infants, rather than mate choice among adults, that gave the First Americans their distinctive hair.

And here’s what a mouse looks like with the EDAR gene....

The world 10000 years ago...

Agriculture is one of the greatest changes ever in the human condition, but whether it was a net improvement for the average person is questionable. There’s a lot of evidence that people were worse fed, and sicker, in a lot of places once they started farming. On the other hand, agriculture supports more people per acre than hunting and gathering, usually by several orders of magnitude, so population pressure is probably a big motive for experimenting with planting seeds.

pop density

But we are still left with an unsolved question. Why, after tens of thousands of years in which human beings showed little inclination to adopt farming, does it develop independently within a five thousand year span in half a dozen spots around the globe? I’ve run into anthropologists who think that it just took that long for populations to reach carrying capacity, but this shows no appreciation at all for the time scale of exponential population expansion. Any human population with room to grow can increase its numbers tens or hundreds of time on a time scale of less than a thousand years. So something other than population-below-carrying-capacity must have kept people from taking up farming for a long, long time. Two possibilities

1) The Ice Age climate wasn’t suited for farming. This explanation was proposed by Robert Boyd, Peter Richerson, and Robert Bettinger. We’ve already seen that Boyd and Richerson argued that the extreme climate swings of past glacial periods favored adaptation via cultural learning (rather than via individual learning or natural selection). These same swings ­– like the dramatic return to glacial condition in the Younger Dryas Cold Event – might have been too much to allow for prolonged settled life in one place, and attendant experiments with agriculture.

Another version of the argument: here’s a recent article, The ant and the grasshopper, presenting evidence that seasonality was the key factor in the the invention and adoption of agriculture. In seasonal environments, there was an incentive to store food to even out annual variations. This encouraged people to settle down, and then to start sowing plants and herding animals. The seasonality factor may explain not only when agriculture happened, but also where.

2) People weren’t genetically adapted to settled life. For example, living a settled life generally means more exposure to disease. It could have taken a long time for humans to evolve resistance to diseases of sedentism. Another possibility: natural selection might have affected behavior over this time. There’s an argument to be made that human beings are a self-domesticated species – that we have selected ourselves, as we have selected other animals, to be tamer, and less aggressive. This agreement is laid out in Richard Wrangham’s recent book, The Paradox of Goodness, and I considered it in a blog post of the same title. Wrangham is mainly concerned with the transition to Homo sapiens, but some of the same morphological changes occur in the transition from early to later Homo sapiens over the past several tens of thousands of years. It may only be in the last ten thousand years or so that many human populations grew tame enough to live in settled communities and take up agriculture. In both ants and humans, behavioral evolution toward increasing cooperation within the species may have been a precursor to the domestication of other species....

Agriculture got started in the Near East by 10,000 years ago, yesterday on Logarithmic History. But a very different agricultural system may have begun around today’s date on the margins of Kuk Swamp in the highlands of New Guinea. This early date is controversial, but agriculture was clearly in place by around 6.5 kya.

The folks at Kuk Swamp were harvesting (and at some point cultivating) root and tree products: taro, yams, and bananas. We know relatively little about the early history of such crops, and their New World counterparts like manioc and sweet potatoes, since they don’t preserve as well archaeologically as grains like wheat, rice, and corn/maize.

And there may be a more consequential difference between roots and tubers, and grains. Many root crops don’t keep well once they’re harvested. Better to leave them in the ground and harvest small amounts as needed. But grains have to be harvested all at once, and then stored. There may be a further socio-political implication to this: in the case of grains, concentrated stores make it easier for tax collectors to step in and appropriate a part of the product. Around the world, grain agriculture eventually ends up associated with complex stratified societies, with elites supported by rents and taxes extracted from a dependent peasantry. Places where root and tree crops were the basis of subsistence were less likely to develop political organization beyond the local level. Highland New Guinea winds up illustrating this, with productive agriculture and dense populations, but tribal-scale politics right up to the mid twentieth century.


The Andes, where the potato was first cultivated, and a succession of empires eventually flourished, may be the exception that proves the rule. At high altitudes, potatoes could be preserved by freeze drying.

James Scott, a political scientist with some anarchist sympathies, has a recent book out, Against the Grain: Deep History of the Earliest States, about the relationship between grains and the state formation. And in an earlier book, The Art of Not Being Governed:An Anarchist History of Upland Southeast Asia, he argues that stateless folk in Southeast Asia sometimes opted for root crops for political reasons – to preserve their independence – more than ecological ones.

8.80 – 8.32 thousand years ago

Farming is now spreading out of the Fertile Crescent. Farmers have crossed the Aegean, and appear in the Balkans and Greece. (They got to Cyprus more than a thousand years earlier.) Farmers have also begun spreading out of the Yellow River and Yangzi River valleys in China.

There’s an argument among philosophers of a utilitarian bent, started by Derek Parfit, over which is better: a world with just a few very happy people (more happiness per capita), or a world crowded with a multitude of people for whom life is just barely worth living (more total happiness)? The choice of the latter has been dubbed the “Repugnant Conclusion.” Whatever the philosophical merits of one possible world or another, there’s little doubt about which direction social evolution usually takes. “God favors the side with the largest battalions” (a saying often attributed to Napoleon, but actually predating him), and agricultural populations have mostly managed to replace hunter-gatherers, even though they are probably worse fed and sicker on average. The DNA evidence shows that in Europe it’s mostly replacement we’re talking about, not just the spread of new technologies. Migrants originally from Anatolia pushed aside indigenous hunter-gatherers without much interbreeding. In Western Europe the replacement wasn’t entirely peaceful. In the north, in what is now Germany and the Low Countries, farmers from the intrusive Linear Pottery (LBK) culture built fortified settlements, and there was an unpopulated no-man’s land between farmer and hunter-gatherer territory. Along the Mediterranean shore, farmers from the intruding Cardial (Impressed Ware) culture sometimes killed foragers, and kept their heads as trophies.

For a while, a decade ago, it looked as if the spread of agriculture might also explain much of the distribution the world’s major language families. Peter Bellwood’s book First Farmers made this case. According to this theory, the first farmers in Europe were speakers of an early Indo-European language that eventually gave rise to most of the languages of Europe, as well as Iran and northern India. We’ll see in days to come on Logarithmic History that the story turns out to be more complicated.

6.64 – 6.28 thousand years ago

The economist Robin Hanson suggests that human population history can be seen as a succession of growth modes, where each mode has a characteristic doubling time. Populations in the hunting mode double roughly every 230,000 years. But by today’s date, enough of the world’s population is practicing agriculture that the farming mode begins to dominate, with a characteristic doubling time of about 860 years.

There’s a puzzle here. Many foraging and farming populations have been observed to grow a lot more quickly than these doubling times would suggest. A recent survey of data on the demography of small-scale societies consistently finds positive growth rates; these would fill the earth many time over in short order. The authors consider various scenarios, with different assumptions about age-specific birth and death rates, to try and reconcile these data with the long-term record of relatively slow growth. Their conclusion is announced in their title: “Periodic catastrophes over human evolutionary history are necessary to explain the forager population paradox.” The expected result is a sawtooth pattern, with populations increasing most of the time, but growth checked by occasional dramatic die-offs.

If this is how human demography has operated in the past, we might expect some consequences for psychology and culture. People should be sensitive to the possibility of catastrophe, and inclined to remember and pass on vivid tales of past catastrophes, even if there is nothing very dangerous going on at the moment.

Also, one response to catastrophe is a military one, ensuring one’s own survival in apocalyptic times at the expense of one’s neighbors. It is notable that the fear of natural disaster is a strong and consistent correlate of warfare....

We tweeted about the first known alcoholic beverage, from China, last week. Today comes another landmark in the history of alcohol, with the first known evidence for beer brewing, from Iran (based on chemical tests of ancient pottery jars). You can find a popular discussion of beer archeology here.

It’s likely that alcohol production goes back earlier than either of these dates. It may even go back before the beginning of agriculture. It’s probably gone on long enough for populations with a long tradition of farming to acquire some genetic adaptations to the availability of alcohol.

People in traditional societies are not just concerned with subsistence – with earning their daily bread by the sweat of their brow. They often put a lot of work into non-subsistence production that raises their prestige. There’s a big literature in anthropology on “costly signaling” (related to conspicuous consumption; for example) concerned with this phenomenon. Archeologist Brian Hayden proposes that the origin of agriculture itself was motivated not so much by subsistence pressures, as by the desire to produce luxury foods for feasts. The potential for alcohol production in particular might have spurred the early domestication of grains.

In that convivial spirit, moving from the distant past to the far future – even to the end of the Universe – here is a toast to the brewmasters, from the last novel by science fiction writer Jack Vance:

The waiter departed to fill the orders. He presently returned with four tankards, deftly served them around the table, then withdrew.

Maloof took up his tankard. “For want of a better toast, I salute the ten thousand generations of brewmasters who, through their unflagging genius, have in effect made this moment possible!”

“A noble toast,” cried Wingo. “Allow me to add an epilogue. At the last moments of the universe, with eternal darkness converging from all sides, surely someone will arise and cry out: ‘Hold back the end for a final moment, while I pay tribute to the gallant brewmasters who have provided us a pathway of golden glory down the fading corridors of time!’ And then, is it not possible that a bright gap will appear in the dark, through which the brewmasters are allowed to proceed, to build a finer universe?”

“It is as reasonable as any other conjecture,” said Schwatzendale. “But now.” The four saluted each other, tilted their tankards, and drank deep draughts....

The story of the evolution of civilization in Mesopotamia used to go like this. As people settled the plains of the Tigris and Euphrates, from the late fifth millennium BCE on they organized themselves around temples that controlled irrigation and distributed rations. From the late fourth millennium, when the written historical record begins, temples were consolidated into city states that warred with one another, until eventually they were united by Sargon of Akkad (in northern Mesopotamia), who founded the first empire in the region around 2300.

But lately it’s been looking like there might have been a whole cycle of empire formation before the invention of writing. The archeological evidence shows that one city, Uruk (home of the legendary Gilgamesh, and probably the same as the Biblical Erech) in southern Mesopotamia had grown to dwarf others in the region by the mid fourth millennium. We find Uruk artifacts over a wide area, from western Iran to northern Syria and southeast Anatolia. These might reflect trade, and probably also settlement, with the establishment of Uruk trading colonies. But at one site at least, something else was going on. Homoukar, in northern Syria, is the site of a city contemporaneous with early Uruk. In 3500 the city was destroyed by hostile forces armed with slings and clay bullets. (The attackers also wiped out what looks like an Uruk trading settlement at Hamoukar, who maybe picked the wrong side to fight on.) The evidence points to Hamoukar having been subsequently occupied by forces from Uruk. We don’t know what kind of administrative control Uruk established, if any, but this does look like long-distance imperialism. Hamoukar is more than 400 miles north of Uruk.

The advent of writing (coming up tomorrow on Logarithmic History) marks a watershed in our knowledge of the past, but we might get a distorted view of social evolution if we assume that the only empires are the ones we know about because people wrote about them. Here are other possible Empires-Before-History, supported by varying levels of evidence or speculation, that we may consider as we continue:

Xia China (A massive flood, said to have triggered the legendary dynasty’s birth, may actually have happened, almost 4 kya) Mycenaean Greece (often treated as a collection of statelets, but maybe a unified state. Mycenean Greeks maybe had better roads than classical Greeks!) The early Aryan Kuru realm in India (known from the Vedas) Cahokia in the American Midwest Chaco Canyon in the American Southwest

> Wheels probably started being used by copper miners in southeastern Europe, in the Carpathians, in the 4th millennium BC. The early wheels were wheelsets, with the wheel fixed solidly to an axle, and the axle rotating. For miners, any alternative to carrying loads of ore on their backs must have been welcome. Miners can smooth a path for their carts, so the problem of moving wheels on uneven terrain is reduced.

Several centuries later, somewhere between the Carpathians and the steppe country north of the Black Sea, another kind of wheel was developed, with the wheel rotating freely around a fixed axle. The new wheel was perfectly suited to a new way of life that developed on the steppes, where nomads followed herds of livestock. Horses might have been the flashiest part of the new lifestyle, but oxcarts, carrying family belongings from one grazing site to another, may have been just as important.

Judging by their reconstructed vocabulary, speakers of Proto-Indo-European – the ancestor of most of the languages of Europe and Northern India – were among those adopting the new technology.


(Actually, looking at the reconstructions, it looks like the adoption of the wheel may have come after Proto-Anatolian – ancestor to Hittite – had branched off from other Indo-European languages.)

Some cultures got into wheels more than others. Sub-Saharan African societies, even including cattle nomads, never adopted the wheel. In the Middle East, wheeled vehicles gave way pack camels sometime between Roman times and the Islamic period. As a result, Islamic states didn’t have to put as much effort into road building as earlier states, and the narrow crooked streets of Islamic cities were made for camels, not carts, to traverse. Wheeled transportation was limited in Japan. And in the New World, wheels are known only from children’s toys.


Things were different in Europe and its cultural offshoots, where wheeled vehicles have exercised a hold on the imagination – especially the male imagination – right up to the present. This is from Richard Bulliet’s recent book, The Wheel: Inventions and Reinventions (p. 33):

Not only is the world racing fraternity composed almost entirely of men, but it has historically recruited very few drivers from East Asia, South Asia, the Middle East and Africa. …[T]he five-thousand-year history of wheels in Indo-European societies – specifically in Europe, including its former colonies, and North America – testifies to an affinity between vehicle driving and male identity in cultures that descend from the Proto-Indo-European linguistic tradition. Since the earliest days of wagon nomads and chariots, through the carriage revolution of the sixteenth century, and down to the automobile era, men brought up in European (and Euro-American) societies have repeatedly linked their manhood to their vehicles.

Here’s one account of the origin of the first system of writing in Mesopotamia:

The immediate precursor of cuneiform writing was a system of tokens. These small clay objects of many shapes – cones, spheres, disks, cylinders, etc. – served as counters in the prehistoric Near East and can be traced to the Neolithic period, starting about 8000 B.C. … The development of tokens was tied to the rise of social structures, emerging with rank leadership, and coming to a climax with state formation. Also, corresponding to the increase of bureaucracy, methods of storing tokens in archives were devised. One of these storage methods employed … simple hollow clay balls in which the tokens were placed and sealed. … Accountants eventually [turned to] imprinting the shapes of the tokens on the surface of the envelopes [balls] prior to enclosing them. An envelope containing seven ovoids, for example, bore seven oval markings. The substitution of signs for tokens was a first step toward writing. Fourth millennium accountants soon realized that the tokens within the envelopes were made unnecessary by the presence of markings on the outer surface. As a result tablets … replaced the hollow envelopes filled with tokens.

Schmandt-Besserac How Writing Came about (Hat tip to commenter Eric Kimbrough for the reference.)

Examples of tokens and corresponding pictographs below:

tokens : writing

And here is Claude Lévi-Strauss (Tristes Tropiques) on the original function of writing:

Writing is a strange invention. One might suppose that its emergence could not fail to bring about profound changes in the conditions of human existence, and that these transformations must of necessity be of an intellectual nature. The possession of writing vastly increases man’s ability to preserve knowledge. It can be thought of as an artificial memory, the development of which ought to lead to a clearer awareness of the past, and hence to a greater ability to organize both present and future. After eliminating all other criteria which have been put forward to distinguish between barbarism and civilization, it is tempting to retain this one at least: there are peoples with, or without, writing; the former are able to store up their past achievements and to move with ever-increasing rapidity towards the goals they have set themselves, whereas the latter, being incapable of remembering the past beyond the narrow margin of individual memory, seem bound to remain imprisoned in a fluctuating history which will always lack both a beginning and any lasting awareness of an aim.

Yet nothing we know about writing and the part it has played in man’s evolution justifies this view. … If we ask ourselves what great innovation writing was linked to, there is little we can suggest on a technical level apart from architecture. … To establish a correlation between the emergence of writing and certain characteristic features of civilization, we must look in quite a different direction. The only phenomenon with writing has always been concomitant is … the integration of large numbers of individuals into a political system and their grading into castes or classes. … At the time when writing first emerged, it seems to have favored the exploitation of human beings rather than their enlightenment. This exploitation, which made it possible to assemble thousands of workers and force them to carry out exhausting tasks, is a … likely explanation of the birth of architecture. My hypothesis, if correct, would oblige us to recognize the fact that the primary function of writing is to facilitate slavery. (To follow up on the preceding post about empires before history: Lévi-Strauss acknowledges that there have been empires without writing, but argues that the lack of writing kept them from enduring long.)

2993-2719 BCE

For more than two centuries scholars have known that most of the languages of Europe, Iran and Northern India, and assorted other places, are sprung from a common source, from an extinct language, never written down, that came to be dubbed Proto-Indo-European (PIE). It’s been a matter of speculation where and when PIE was spoken. Now, just in the last few years, it looks like the major questions about Indo-European origins are being answered. Research on ancient DNA (check out David Reich’s Who We Are and How We Got Here) has overturned an earlier view (which seemed viable to many researchers even a few years ago) that there were just two major waves of migration into Europe: hunter-gatherers 40 thousand years ago, and farmers from Anatolia starting 7000 years ago. But it turns out that there was also a later massive wave of immigration, coming from the grasslands north of the Black Sea, about 2800 BCE. This migration replaced much of the population of northern Europe, and contributed substantially to southern Europe as well. (See here and here for Logarithmic History blog posts on the possible pre-Indo-European roots of Indo-Europeans.) The migration is a perfect fit for what historical linguists have been saying for a long time. For example, the newcomers brought ox-drawn wagons and wheels with them, matching vocabulary in PIE. (Here’s one of the best books on the subject, by archeologist David Anthony, written even before the latest DNA evidence came in. If you want to delve deeply into the latest DNA news, on Indo-European origins and related topics, here’s a blog for you.)

The intellectual history of the Indo-European question has not just been about pure and objective scholarship; it’s been bound up with the bloody history of the twentieth century.

In 1926, V. Gordon Childe, in his day probably the preeminent prehistoric archeologist in the English-speaking world, wrote a book addressing the topic of Indo-European origins. Synthesizing linguistic and archeological evidence, he named a likely place – the steppes of Ukraine and Southern Russia – and a time – the late Neolithic or Copper age, well after the advent of agriculture, but before the Bronze Age. (The corresponding archeological culture is now called the Yamnaya. However the very earliest split in the IE tree, bringing Hittite ancestors to Anatolia, comes earlier.) He argued that Indo-European speakers had migrated west to conquer big swathes of territory in Europe (Corded Ware and Bell Beaker cultures), and, later, east and south into Iran and India. In other words, he defended what now looks like the correct theory. This wasn’t just a lucky guess. He got it right mostly because he took historical linguistics seriously, as a hard science in its own right.

Childe’s book was entitled “The Aryans: A Study of Indo-European Origins,” and this suggests a problem. Childe acknowledged that the title was a misnomer. Strictly speaking “Aryan” applies only to speakers of Indo-European languages in Iran and India; Childe called PIE speakers “Aryans” simply because it made a better book title. But the title alone was not really the problem. Childe knew that Indo-European prehistory, and the Aryan label, were popular with the nationalist German Right. Childe had no sympathy for German nationalism. He was an Australian who lived most of his life in England. He was also a lifelong socialist and a man of the Left. In fact his book aimed at deflating nationalist claims. He located the Indo-European homeland in Eastern Europe, not Germany or Scandinavia, as some claimed. And he denied that the “Aryans” had any special racial genius. He did think that Indo-European languages (not a racial character) were “exceptionally delicate and flexible instruments of thought” that facilitated later intellectual developments. (This one probably won’t fly. Linguists nowadays mostly don’t think grammar has that much effect on cognition.) And he speculated that “Aryans” might have had an advantage over other folk simply by virtue of being large and well-fed. (This one isn’t totally crazy. Indo-Europeans were apparently big guys, like the Nilotic cattle herders of East Africa to whom they show some interesting convergent cultural similarities.) Nonetheless, the whole subject grew increasingly uncomfortable as the 1920s moved into the 30s. Childe let the book go out of print, and scarcely referred to it in the course of a long productive career.

Beyond killing tens of millions of people, Nazism also had a long lasting deforming effect on intellectual life. For most of the later twentieth century Anglo-American archeologists went out of their way to avoid topics like migration, barbarian invasions, and population replacements. These were, in today’s jargon, problematic. For example, it was clear that something dramatic happened over a huge stretch of Europe, from Poland to the Netherlands, in the early third millennium BCE: settled life gave way to nomadism, farming to cattle raising. But this was written off as a technological shift, the Secondary Products Revolution. (To be fair, there were some exceptions among archeologists, like David Anthony and Marija Gimbutas, and many exceptions among linguists. Jared Diamond also got it right.) In some ways, then, we’re just beginning to recover, intellectually, from the Second World War.

2560 BCE

You might think that with the Egyptian pyramids being famous for thousands of years (they’re the only one of the Seven Wonders of the Ancient World still standing) there wouldn’t be much new to say about them. But you’d be wrong. The Egyptians wrote down virtually nothing about their architectural methods; they may have worked with some kind of 3-D models – the Bronze Age version of Computer-Aided Design – rather than anything like blueprints. So we haven’t really known much about how the pyramids were built. In particular, it’s been a real puzzle how they moved building blocks to near the top of the pyramid in the later stages of construction. If blocks were moved along a straight ramp up the side of the pyramid, the ramp in the last stages would have had to be a mile long, and contained as much material as the pyramid itself. It also wouldn’t have fit on the Giza plateau. Recently, Jean-Pierre Houdin, a French architect, may have figured out how the problem was solved in the case of the largest pyramid, the Great Pyramid built for King Khufu (Cheops). According to Houdin, the builders used an external ramp for the early stages of construction. But they also built a vaulted internal ramp, spiraling around inside the pyramid, and moved blocks up it for the later stages. (And the builders economized by dismantling the external ramp and using it for construction material.) Houdin revealed his theory in 2005. Both before and since then he has put a huge amount of work into understanding how the Great Pyramid was built. For example, he may also have come up with an explanation for the 150 foot-long, narrow, slanting Grand Gallery in the pyramid: it looks like it was used to run counterweights on a trolley that helped to bring up some of the heaviest stones, the granite blocks used to reinforce the King’s Chamber....

1761-1555 BCE

The time of the Biblical Patriarchs. Abraham, Isaac, and Jacob, is sometimes called the Patriarchal Age. If there is a kernel of truth to the Biblical stories, the Patriarchal Age probably goes back to the early third millennium. But the concept applies more broadly. A recent title says it: “A recent bottleneck of Y chromosome diversity coincides with a global change in culture.” This figure shows it. patriarchy The left panel shows effective population sizes based on Y chromosome DNA, transmitted down the male line. The right panel shows effective population sizes based mitochondrial DNA, transmitted down the female line. The dramatic dip on the left panel, where effective population sizes go way down in the last ten thousand years, means that there was a period, from the initial spread of major language families to near the dawn of history, where just a few men were leaving lots of descendants in the male line. This must reflect a time when polygyny – some men taking multiple wives, others not reproducing at all – was common. But this pattern probably reflects more than just polygyny. It probably also reflects a continuing advantage, carried over many generations, for some male lines of descent. In other words, back in the day, not just did Lord Y (or whoever) have many wives and many sons, but his sons, his sons’ sons. his son’s son’s sons, and so on, had many offspring. This probably implies some kind of long-term social memory, such that that the “Sons of Y” or the “House of Y” had a privileged position for many generations.

Australian Aborigines, subjects of our last two posts, often have high frequencies of polygyny, but mostly don’t keep track of genealogies over the long term. Men can tell you what kin terms they apply to other people, but they mostly don’t know their ancestry past a few generations. If I’m an Aborigine, it’s enough to know that my father called some other man “brother,” to know that that I call that man’s children my “siblings.” I don’t have to know the actual genealogy. But many Eurasian societies have been different. People can give you a line of begats stretching back many generations. For example, Kirghiz boys from a young age were expected to be able to tell you their “seven fathers”, i.e. their father, their father’s father, and so on, for seven generations. Having prominent ancestors inthe male line is a form of social capital. Even very large groups may claim descent from ancestors going way back. These stories – the tribes of Israel going back to the sons of Jacob, Greek patrilineages going back to the sons of Hellen (a guy, no relation to Helen of Troy), Indian Brahmins belonging to different ancestral gotras (patrilineal clans) going back to Vedic times – must have been heavily fictionalized. But maybe not completely.

Eurasian history is often told as the story the rise of states and empires. But it’s also the story of the rise of patrilineal descent groups (and the heavy policing of female sexuality to make sure of paternity in the male line). One thing we’ll see in posts to come is how the relationship between State and Clan played out differently in different civilizations....

The Bronze Age ends with a bang. Recently news stories covered the find of the site of a massive battle in 1250 BCE on the banks of the Tollense river, near the Baltic Sea, probably involving armies of thousands of warriors. Hundreds were killed. The fighters were professional warriors, and many probably came from some distance away.

We have no written record, or even legends, of what was going on here, but in subsequent centuries there are massive disruptions in the civilized world. In the 1100s, the palaces of the Mycenaean civilization in Greece are destroyed, By 1050 BCE, Greece descends into a dark age. The period probably marks the arrival of the Dorian dialects of Greek in the Peloponnese, and the movement of Achaean refugees to Ionia. There is also wide destruction and a collapse of social complexity in Anatolia, Syria, and Canaan. In 1177 BCE, the Egyptians hold an invasion by the “Sea Peoples.” Their provenance is a matter of dispute, but may have included some Mycenaeans, who would go on to settle in Canaan as Philistines.

The causes of this collapse are (as of later Dark Ages) are unsettled.

A recent article shows that the subsequent regression in social complexity may have left its mark on human genes. The chart below show how much Europeans were migrating (top panel).

end bronze migrate

Several episodes of large scale movement stand out, like the Neolithic, following the spread of agriculture, and the Bronze Age, following the arrival of Indo-European speakers. By contrast, the end of the Bronze Age shows an apparent decline in population mobility, which only picks up as the subsequent Iron Age gets underway....

The world at 1000 BCE 1 Reply Here’s a quick look at the world around 1000 BCE

The world population is about 50 million.

The Bantu expansion is just beginning, from a homeland on the present Nigeria/Cameroon border. It will eventually cover most of Africa south of the equator. The expansion is sometimes told as a story of first farmers replacing hunter-gatherers. But, as with the Indo-European expansion, this now looks to be too simple. Other farmers and herders reached east Africa before the Bantu; traces of their languages survive as eastern Bantu substrates. So the Bantu had something extra – social organization? malaria resistance? – going for them.

Seafarers with roots in the Lapita culture have already reached Western Polynesian – Samoa and Tonga, previously uninhabited.

The Olmec are flourishing in Meso-America. A controversial find (the Cascajal block) suggests they are just taking up writing.

In China, the Mandate of Heaven has passed from the Shang Dynasty to the Zhou.

In the Near East and Eastern Mediterranean, the Late Bronze Age collapse has opened up space for smaller states. Tyre and other Phoenician city-states are sailing the Mediterranean. Phoenicians are using an alphabet that Greeks will eventually adapt. There might be other borrowings: Odysseus might originally have been Phoenician. At least that was the argument of the early twentieth century French diplomat and classicist Victor Bérard. He thought that Homer had folded an earlier Phoenician picaresque tale into his epic. James Joyce was very taken with this theory; Joyce’s Levantine Leopold Bloom owes something to Bérard’s Phoenician Odysseus.

Further south, Philistines and Israelites have been duking it out, with Israelites gaining the upper hand under David* (king from 1010 to 970 BCE). The Iron Age conventionally begins now, with the widespread use of iron – more abundant and cheaper than bronze.

On the steppe, horses have long been domesticated, but people are now learning to make effective use of cavalry – fighting in formation and firing volleys from horseback. This is the beginning of 2500 years in which the division between Steppe and Sown will be central to Eurasian history.

  • Everybody knows that David killed Goliath (1 Samuel 17). However, according to 2 Samuel 21:19, Goliath was killed by Elhanan of Bethlehem. (Depending on which version of the Bible you use, the victim might be given as the brother of Goliath, but the italicised bit is a later interpolation. It’s plain Goliath originally.) Probably the Elhanan story is the original one, and the whole David-and-Goliath story amounts to later resume-padding on the part of David at the expense of a subordinate. See The Historical David: The Real Life of an Invented Hero for this and other demonstrations of how we can recover likely truths from historical texts.

675-528 BCE

The period leading up to historical times saw the rise of patrilineal descent groups (and maybe some transitions from matrilineal descent) across Eurasia. Different civilizations found different ways of accommodating these groups. In China, patrilineal clans go as far back as we have any historical records, back to the Shang dynasty. Confucius (551-479 BCE) in some ways represented a break with this past. He thought a wise prince should select ministers based on their ability rather than their lineage. But China could never be governed by bureaucrats alone, and Chinese states found themselves depending on extended families and clans to help rule the country. The Confucian state exalted filial piety, obedience to one’s elders, and ancestor worship along with obedience to the Emperor. When an official told Confucius “In my country there is an upright man named Kung. When his father stole a sheep, Kung bore witness against him,” Confucius replied, “The upright men in my community are different from this. The father conceals the misconduct of the son. The son conceals the misconduct of the father. Uprightness is to be found in this.” The resulting social compact – Arthur Wolf, an anthropologist of China calls it “state patriarchy” – was extraordinarily resilient. In days to come we will see how it kept bouncing back from one disruption after another, like one of those heavy-bottomed dolls you just can’t keep knocked over.

By contrast, the classical city-states of Greece and Rome went through a series of social revolutions early in their history where both kings and patrilineages lost their exalted position. This argument was developed back in the nineteenth century by the French historian Numa Denis Fustel de Coulanges. In his book The Ancient City, Fustel showed how ancestor worship and clan loyalty gave way to civic institutions. For example in Athens the democratic reformer Cleisthenes (570-508) replaced old-style subdivisions of the populace based on descent with new subdivisions based on residence. For a time, the classical city-state commanded intense loyalty from its citizens, and displayed an exceptionally high level of military effectiveness.

China’s revolution against the old order of elders, extended family, and clan waited until the twentieth century, and took a horrific toll on the population. Even today some of the old ways persist. The putative patrilineal descendants of Confucius, more than two million strong, have recently been updating their genealogies....

Asabiya and metaethnic frontiers 3 Replies In 390 BCE an army of Gauls, 30 thousand strong, marched out of northern Italy into Latium, an area that included Rome. They defeated a Roman army, sacked and burned Rome, and left only after being paid a large tribute. This marked a turning point for Rome, which resolved never again to allow such a disaster. Over the next century, Romans used a mixture of coercion and consent to bind their Italian allies more closely to them. Attempted secession was punished. But those who accepted their position as allies were not simply crushed and plundered (as in many other empires) but granted some or all of the privileges of Roman citizenship in return for military contributions. Membership in the Roman confederation was attractive enough that many Italian states sought it voluntarily.

The history of Greece during this period is different. Greek city-states never united. In the aftermath of the bloody Peloponnesian war, different city-states went on fighting for supremacy, until they were finally conquered by an outside power, Macedonia.

Peter Turchin is an ecologist-turned-social scientist who thinks that the contrast between Rome and Greece illustrates some general laws of history. According to Turchin, the rise and fall of empires is partly conditioned on the strength of “asabiya,” or social solidarity. (He borrows the term from the medieval Arab historian ibn Khaldun.) The strength of states depends not just on material factors like population size and wealth, but also on morale – on the willingness of citizens to work together for the common good (which includes punishing free-riders). Asabiya was high in early Rome; in Greece, by contrast, while individual city-states might evoke strong group feeling, there was little willingness to cooperate for the good of Greece as a whole.

metaethnicAsabiya in turn (according to Turchin) develops especially along “metaethnic frontiers,” where very different cultures meet and clash. The illustration (by me, writing about matrilocal asabiya, not Turchin) shows the general idea. When culture changes little, or changes gradually, with distance (a), there is little basis for uniting independent polities (stars) into enduring larger units, and alliances (dotted lines) shift constantly. Along the metaethnic frontier (b), the opposite is true (solid lines show cohesive enduring units). Think Game of Thrones versus Lord of the Rings: it’s easier to get men and elves and dwarves to work together when they are fighting an army of orcs serving the Dark Lord.

Sometimes a metaethnic frontier develops where major religions or ideologies clash. But in the Roman case, the metaethnic frontier ran along the line dividing civilized Italians from barbarian Celts. Greece, by contrast, experienced a surge in fellow-feeling when Athens and Sparta fought together to defeat Persia, but this was too short lived to lead to a unified state.

Also worth reading is Empires of Trust, tracing parallels between the expansion of early Rome and of the United States – two immense states on the western frontiers of civilization. (The book is better than most comparing America and Rome.)...

After centuries of division into warring states, China was united in 221 BCE, under the short-lived Qin and then the long-lived Han dynasties. (Here’s a dynamic map showing the process of unification.) Just a few years later, in 209 BCE, the nomads of the steppe north of China were united under the Xiongnu confederation.

China, like Rome, provides an instance of empire formation along a metaethnic frontier between civilized and barbarian peoples. But it also differs from the Roman case. The Roman frontier kept pushing into barbarian territory for many centuries. The descendants of Asterix and Obelisk would largely forget their identity as Gauls, and become Romans, speaking a dialect of Latin.


But in the Far East, the steppe north of China would not support agriculture, and the people who lived there would continue their nomad way of life and retain a separate ethnic identity. For centuries after 221 BCE, China held off the barbarians by a combination of military measures (notably of course the Great Wall) and bribery (poorly disguised as “gifts” from Emperor to subject). The Xiongnu held together as a centralized state because their ruler managed the flow of trade and tribute from China. In effect, Qin/Han and Xiongnu were “mirror empires,” facing off across the line between Sown and Steppe.

101-205 CE

If a man were called to fix the period in the history of the world, during which the condition of the human race was most happy and prosperous, he would, without hesitation, name that which elapsed from the death of Domitian [96 CE] to the accession of Commodus [180 CE]. The vast extent of the Roman empire was governed by absolute power, under the guidance of virtue and wisdom. The armies were restrained by the firm but gentle hand of four successive emperors, whose characters and authority commanded involuntary respect.

Edward Gibbon, The Decline and Fall of the Roman Empire, Chapter 3 Gibbon doesn’t include China in this assessment of the state of the world, but for that country too, under the Eastern Han dynasty, there was a period of stability and prosperity, lasting from the death of the usurper Wang Mang in 24 CE to the outbreak of the Yellow Turban peasant uprising in 184 CE. During this time, the Roman and Han empires so completely dominated their respective portions of Eurasia that they enjoyed relative peace. Toward the end of the second century CE, both empires had populations around 50-60 million; world population was perhaps 190 million. In the succeeding centuries both empires would experience major population declines and political collapse. As a result, the world’s total population may have declined as well.

Of course Gibbon’s view is a retrospective one, and didn’t anticipate the vast rise in standards of living that eventually followed the industrial revolution.

(After this I’ll give dates as numbers without the “CE”.)

1. Economic Growth Has a History

1.1. The Old and Middle Stone Ages

1.1.1. The Old and Middle Stone Ages



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